What is Active / Active Array ? - Storage

This is a discussion on What is Active / Active Array ? - Storage ; Could it be possible to give me some advice what is the difference between "Active / Active" Arrays and "Active / Passive" Arrays for Storage Processors ? Thanks...

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  1. What is Active / Active Array ?

    Could it be possible to give me some advice what is the difference between
    "Active / Active" Arrays and "Active / Passive" Arrays for Storage
    Processors ?

    Thanks




  2. Re: What is Active / Active Array ?

    You might want to specify where you have seen these terms and in relation to
    what brand ?
    Also, as the storage vendor who is actually using these terms for an
    explanation

    rgds,
    Edwin.



    "Peter" wrote in message
    news:%23y0L7tgFHHA.4768@TK2MSFTNGP05.phx.gbl...
    > Could it be possible to give me some advice what is the difference between
    > "Active / Active" Arrays and "Active / Passive" Arrays for Storage
    > Processors ?
    >
    > Thanks
    >
    >
    >




  3. Re: What is Active / Active Array ?

    Peter wrote:
    > Could it be possible to give me some advice what is the difference between
    > "Active / Active" Arrays and "Active / Passive" Arrays for Storage
    > Processors ?
    >
    > Thanks
    >
    >
    >


    Typically, Active-Active means that IO being read from or written to a
    particular logical device (LUN) can happen from either of two redundant
    storage controllers, or storage processors as you put it.

    Active-passive configurations will typically have a logical device or
    LUN "owned" by one of two redundant controllers. When the controller
    which owns a LUN fails or the host loses access to that controller, the
    other (passive) controller takes ownership of the LUN and host IO is
    then serviced from this new controller.

    Active-active is better in every case I can think of. The host requires
    less sophisticated multipathing software since it doesn't need to have
    any knowledge of which controller owns a LUN and doesn't need to know
    how initiate a transfer of ownership. It can always send IO down any
    available path.

    I think it's pretty common to hear a vendor tell you that their storage
    array is active-active when it is in fact just two active-passive
    controllers which provide failover for each other. That might sound
    strange, but imagine two LUNs, one owned by each controller in such a
    system. Both controllers are actively servicing IO, but as far as any
    particular LUN is concerned the configuration is actually
    active-passive. Another trick vendors can play is to have a back-end
    connection between two active-passive controllers so the host can
    actually send IO to either controller, but in fact only one is doing all
    the work. This is a step up from a simple active-passive configuration
    because your hosts can always send IO down any available path, but it's
    not truly active-active. I've also heard of possible performance
    penalties for sending IO to the passive controller in this situation,
    but I'm sure that issue is specific to however the vendor has
    implemented that back-end connection between controllers.

  4. Re: What is Active / Active Array ?

    Dear JM,

    Many thanks for your advice.

    We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active / Passive
    array ?

    Regards,
    Peter
    "JM" wrote in message
    news:emY9OU8FHHA.4464@TK2MSFTNGP03.phx.gbl...
    > Peter wrote:
    >> Could it be possible to give me some advice what is the difference
    >> between "Active / Active" Arrays and "Active / Passive" Arrays for
    >> Storage Processors ?
    >>
    >> Thanks
    >>
    >>
    >>

    >
    > Typically, Active-Active means that IO being read from or written to a
    > particular logical device (LUN) can happen from either of two redundant
    > storage controllers, or storage processors as you put it.
    >
    > Active-passive configurations will typically have a logical device or LUN
    > "owned" by one of two redundant controllers. When the controller which
    > owns a LUN fails or the host loses access to that controller, the other
    > (passive) controller takes ownership of the LUN and host IO is then
    > serviced from this new controller.
    >
    > Active-active is better in every case I can think of. The host requires
    > less sophisticated multipathing software since it doesn't need to have any
    > knowledge of which controller owns a LUN and doesn't need to know how
    > initiate a transfer of ownership. It can always send IO down any
    > available path.
    >
    > I think it's pretty common to hear a vendor tell you that their storage
    > array is active-active when it is in fact just two active-passive
    > controllers which provide failover for each other. That might sound
    > strange, but imagine two LUNs, one owned by each controller in such a
    > system. Both controllers are actively servicing IO, but as far as any
    > particular LUN is concerned the configuration is actually active-passive.
    > Another trick vendors can play is to have a back-end connection between
    > two active-passive controllers so the host can actually send IO to either
    > controller, but in fact only one is doing all the work. This is a step up
    > from a simple active-passive configuration because your hosts can always
    > send IO down any available path, but it's not truly active-active. I've
    > also heard of possible performance penalties for sending IO to the passive
    > controller in this situation, but I'm sure that issue is specific to
    > however the vendor has implemented that back-end connection between
    > controllers.




  5. Re: What is Active / Active Array ?

    Peter wrote:
    > Dear JM,
    >
    > Many thanks for your advice.
    >
    > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active / Passive
    > array ?
    >
    > Regards,
    > Peter


    By my definition, any EMC Clariion is going to be an active / passive
    array. They may call it active / active, but like I said it's really
    just two SPs which are active / passive partners for each other. If
    your host has one connection to each SP, it will only be able to send IO
    down the path to the SP which owns each individual LUN. Typically you
    would install EMC's PowerPath software to help the host understand how
    to manage the multiple paths back to the Clariion.

  6. Re: What is Active / Active Array ?

    I would agree with JM, however one small remark to further specify for a CX;

    if one LUN is owned by one SP and the next LUN is owned by the other SP,
    than IO will be processed by both SP's
    (at least that is my experience with CX)

    Not sure if this fully classify as an Active/Active as JM describes, but by
    spreading LUNs accross the SPs you will get the benifit of both SP's
    processing IO.



    "JM" wrote in message
    news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > Peter wrote:
    > > Dear JM,
    > >
    > > Many thanks for your advice.
    > >
    > > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /

    Passive
    > > array ?
    > >
    > > Regards,
    > > Peter

    >
    > By my definition, any EMC Clariion is going to be an active / passive
    > array. They may call it active / active, but like I said it's really
    > just two SPs which are active / passive partners for each other. If
    > your host has one connection to each SP, it will only be able to send IO
    > down the path to the SP which owns each individual LUN. Typically you
    > would install EMC's PowerPath software to help the host understand how
    > to manage the multiple paths back to the Clariion.




  7. Re: What is Active / Active Array ?

    Dear JM and Edwin,

    Thank you for your advice.

    A consultant suggests that for all LUNs in the same RAID Group should be
    assigned to the same SP. Is it sensible ?

    Regards,
    Peter

    "Edwin vMierlo" wrote in message
    news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >I would agree with JM, however one small remark to further specify for a
    >CX;
    >
    > if one LUN is owned by one SP and the next LUN is owned by the other SP,
    > than IO will be processed by both SP's
    > (at least that is my experience with CX)
    >
    > Not sure if this fully classify as an Active/Active as JM describes, but
    > by
    > spreading LUNs accross the SPs you will get the benifit of both SP's
    > processing IO.
    >
    >
    >
    > "JM" wrote in message
    > news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> Peter wrote:
    >> > Dear JM,
    >> >
    >> > Many thanks for your advice.
    >> >
    >> > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /

    > Passive
    >> > array ?
    >> >
    >> > Regards,
    >> > Peter

    >>
    >> By my definition, any EMC Clariion is going to be an active / passive
    >> array. They may call it active / active, but like I said it's really
    >> just two SPs which are active / passive partners for each other. If
    >> your host has one connection to each SP, it will only be able to send IO
    >> down the path to the SP which owns each individual LUN. Typically you
    >> would install EMC's PowerPath software to help the host understand how
    >> to manage the multiple paths back to the Clariion.

    >
    >




  8. Re: What is Active / Active Array ?

    You do not have to assign them to the same SP
    I would recommend that you spread your LUNs over the two SP's, to ensure
    both SP's are processing IO

    being in the same RAID group has nothing to do with which SP owns the LUN
    (from experience)

    unless the application or configuration is specific, and there are good
    technical reasons (which we cannot see in small posts in the newsgroups)
    then there _might_ be a reason to assign all LUNs in a RAIDgroup to the same
    SP.

    Ask the consultant: why all luns in the same raidgroup to the same sp ?
    being a consultant, he/she must back up suggestions with technical
    reasons... (right ?)

    HTH,
    _Edwin.

    "Peter" wrote in message
    news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > Dear JM and Edwin,
    >
    > Thank you for your advice.
    >
    > A consultant suggests that for all LUNs in the same RAID Group should be
    > assigned to the same SP. Is it sensible ?
    >
    > Regards,
    > Peter
    >
    > "Edwin vMierlo" wrote in message
    > news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >I would agree with JM, however one small remark to further specify for a
    > >CX;
    > >
    > > if one LUN is owned by one SP and the next LUN is owned by the other SP,
    > > than IO will be processed by both SP's
    > > (at least that is my experience with CX)
    > >
    > > Not sure if this fully classify as an Active/Active as JM describes, but
    > > by
    > > spreading LUNs accross the SPs you will get the benifit of both SP's
    > > processing IO.
    > >
    > >
    > >
    > > "JM" wrote in message
    > > news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >> Peter wrote:
    > >> > Dear JM,
    > >> >
    > >> > Many thanks for your advice.
    > >> >
    > >> > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /

    > > Passive
    > >> > array ?
    > >> >
    > >> > Regards,
    > >> > Peter
    > >>
    > >> By my definition, any EMC Clariion is going to be an active / passive
    > >> array. They may call it active / active, but like I said it's really
    > >> just two SPs which are active / passive partners for each other. If
    > >> your host has one connection to each SP, it will only be able to send

    IO
    > >> down the path to the SP which owns each individual LUN. Typically you
    > >> would install EMC's PowerPath software to help the host understand how
    > >> to manage the multiple paths back to the Clariion.

    > >
    > >

    >
    >




  9. Re: What is Active / Active Array ?

    Dear Edwin,

    I hold the same opinion as yours. I have asked him and he says that it is
    EMC's advice. However, I have searched PowerLink but there is no article
    mentioning it.

    Besides, if I choose auto assign, the first LUN in the same RAID group
    created will choose SPA, the second one choose SPB, the third one choose SPA
    that is different from what he says.

    Peter



    "Edwin vMierlo" wrote in message
    news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > You do not have to assign them to the same SP
    > I would recommend that you spread your LUNs over the two SP's, to ensure
    > both SP's are processing IO
    >
    > being in the same RAID group has nothing to do with which SP owns the LUN
    > (from experience)
    >
    > unless the application or configuration is specific, and there are good
    > technical reasons (which we cannot see in small posts in the newsgroups)
    > then there _might_ be a reason to assign all LUNs in a RAIDgroup to the
    > same
    > SP.
    >
    > Ask the consultant: why all luns in the same raidgroup to the same sp ?
    > being a consultant, he/she must back up suggestions with technical
    > reasons... (right ?)
    >
    > HTH,
    > _Edwin.
    >
    > "Peter" wrote in message
    > news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >> Dear JM and Edwin,
    >>
    >> Thank you for your advice.
    >>
    >> A consultant suggests that for all LUNs in the same RAID Group should be
    >> assigned to the same SP. Is it sensible ?
    >>
    >> Regards,
    >> Peter
    >>
    >> "Edwin vMierlo" wrote in message
    >> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >> >I would agree with JM, however one small remark to further specify for a
    >> >CX;
    >> >
    >> > if one LUN is owned by one SP and the next LUN is owned by the other
    >> > SP,
    >> > than IO will be processed by both SP's
    >> > (at least that is my experience with CX)
    >> >
    >> > Not sure if this fully classify as an Active/Active as JM describes,
    >> > but
    >> > by
    >> > spreading LUNs accross the SPs you will get the benifit of both SP's
    >> > processing IO.
    >> >
    >> >
    >> >
    >> > "JM" wrote in message
    >> > news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> >> Peter wrote:
    >> >> > Dear JM,
    >> >> >
    >> >> > Many thanks for your advice.
    >> >> >
    >> >> > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    >> > Passive
    >> >> > array ?
    >> >> >
    >> >> > Regards,
    >> >> > Peter
    >> >>
    >> >> By my definition, any EMC Clariion is going to be an active / passive
    >> >> array. They may call it active / active, but like I said it's really
    >> >> just two SPs which are active / passive partners for each other. If
    >> >> your host has one connection to each SP, it will only be able to send

    > IO
    >> >> down the path to the SP which owns each individual LUN. Typically you
    >> >> would install EMC's PowerPath software to help the host understand how
    >> >> to manage the multiple paths back to the Clariion.
    >> >
    >> >

    >>
    >>

    >
    >




  10. Re: What is Active / Active Array ?

    "he says that it is EMC's advice"

    well... he better back that up with a technical article from EMC

    or you need to talk to EMC directly, because I have never heard that, and I
    have some experience with different models in the CX-series.





    "Peter" wrote in message
    news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    > Dear Edwin,
    >
    > I hold the same opinion as yours. I have asked him and he says that it is
    > EMC's advice. However, I have searched PowerLink but there is no article
    > mentioning it.
    >
    > Besides, if I choose auto assign, the first LUN in the same RAID group
    > created will choose SPA, the second one choose SPB, the third one choose

    SPA
    > that is different from what he says.
    >
    > Peter
    >
    >
    >
    > "Edwin vMierlo" wrote in message
    > news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > > You do not have to assign them to the same SP
    > > I would recommend that you spread your LUNs over the two SP's, to ensure
    > > both SP's are processing IO
    > >
    > > being in the same RAID group has nothing to do with which SP owns the

    LUN
    > > (from experience)
    > >
    > > unless the application or configuration is specific, and there are good
    > > technical reasons (which we cannot see in small posts in the newsgroups)
    > > then there _might_ be a reason to assign all LUNs in a RAIDgroup to the
    > > same
    > > SP.
    > >
    > > Ask the consultant: why all luns in the same raidgroup to the same sp ?
    > > being a consultant, he/she must back up suggestions with technical
    > > reasons... (right ?)
    > >
    > > HTH,
    > > _Edwin.
    > >
    > > "Peter" wrote in message
    > > news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > >> Dear JM and Edwin,
    > >>
    > >> Thank you for your advice.
    > >>
    > >> A consultant suggests that for all LUNs in the same RAID Group should

    be
    > >> assigned to the same SP. Is it sensible ?
    > >>
    > >> Regards,
    > >> Peter
    > >>
    > >> "Edwin vMierlo" wrote in

    message
    > >> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >> >I would agree with JM, however one small remark to further specify for

    a
    > >> >CX;
    > >> >
    > >> > if one LUN is owned by one SP and the next LUN is owned by the other
    > >> > SP,
    > >> > than IO will be processed by both SP's
    > >> > (at least that is my experience with CX)
    > >> >
    > >> > Not sure if this fully classify as an Active/Active as JM describes,
    > >> > but
    > >> > by
    > >> > spreading LUNs accross the SPs you will get the benifit of both SP's
    > >> > processing IO.
    > >> >
    > >> >
    > >> >
    > >> > "JM" wrote in message
    > >> > news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >> >> Peter wrote:
    > >> >> > Dear JM,
    > >> >> >
    > >> >> > Many thanks for your advice.
    > >> >> >
    > >> >> > We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    > >> > Passive
    > >> >> > array ?
    > >> >> >
    > >> >> > Regards,
    > >> >> > Peter
    > >> >>
    > >> >> By my definition, any EMC Clariion is going to be an active /

    passive
    > >> >> array. They may call it active / active, but like I said it's

    really
    > >> >> just two SPs which are active / passive partners for each other. If
    > >> >> your host has one connection to each SP, it will only be able to

    send
    > > IO
    > >> >> down the path to the SP which owns each individual LUN. Typically

    you
    > >> >> would install EMC's PowerPath software to help the host understand

    how
    > >> >> to manage the multiple paths back to the Clariion.
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >




  11. Re: What is Active / Active Array ?


    I have heard this, but it only applies to ATA disks and not for Fibre
    Channel disks in Clariion arrays. The way it was explained to me was
    that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    Fibre Channel RAID group, each disk essentially has a connection to each
    SP, so the link control card (LCC) in the disk array enclosure (DAE) can
    simply pass on commands to each individual disk. In an ATA DAE, the
    LCCs are actually called BCCs* (I don't recall what the "B" stands for,
    I've also heard BCCs called "paddle cards"). The BCCs incur some
    overhead when commands come from different SPs which are bound for the
    same disk. It has to flip-flop back and forth and dump them to the
    single ported ATA disk. This may not be technically accurate but it's
    the way I remember it being explained.

    The rule of thumb I've heard is that all LUNs in an ATA RAID group
    should be owned by a single SP. For a Fibre Channel RAID group it
    doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    trespass and simply being forgetful we currently don't obey this rule to
    the letter. Where we've mixed and matched LUN ownership in ATA RAID
    groups we have yet to see any problems, performance or otherwise.

    * Early incarnations of Clariion ATA DAEs had many problems with the
    firmware on these BCC cards, which is called FRUMON code. I had more
    than one 20 hour day thanks to these things around the FLARE 13 days.
    They seem to have worked out the kinks since then, we've been extremely
    stable on ATA since about FLARE 16.

    Edwin vMierlo wrote:
    > "he says that it is EMC's advice"
    >
    > well... he better back that up with a technical article from EMC
    >
    > or you need to talk to EMC directly, because I have never heard that, and I
    > have some experience with different models in the CX-series.
    >
    >
    >
    >
    >
    > "Peter" wrote in message
    > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >> Dear Edwin,
    >>
    >> I hold the same opinion as yours. I have asked him and he says that it is
    >> EMC's advice. However, I have searched PowerLink but there is no article
    >> mentioning it.
    >>
    >> Besides, if I choose auto assign, the first LUN in the same RAID group
    >> created will choose SPA, the second one choose SPB, the third one choose

    > SPA
    >> that is different from what he says.
    >>
    >> Peter
    >>
    >>
    >>
    >> "Edwin vMierlo" wrote in message
    >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >>> You do not have to assign them to the same SP
    >>> I would recommend that you spread your LUNs over the two SP's, to ensure
    >>> both SP's are processing IO
    >>>
    >>> being in the same RAID group has nothing to do with which SP owns the

    > LUN
    >>> (from experience)
    >>>
    >>> unless the application or configuration is specific, and there are good
    >>> technical reasons (which we cannot see in small posts in the newsgroups)
    >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup to the
    >>> same
    >>> SP.
    >>>
    >>> Ask the consultant: why all luns in the same raidgroup to the same sp ?
    >>> being a consultant, he/she must back up suggestions with technical
    >>> reasons... (right ?)
    >>>
    >>> HTH,
    >>> _Edwin.
    >>>
    >>> "Peter" wrote in message
    >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >>>> Dear JM and Edwin,
    >>>>
    >>>> Thank you for your advice.
    >>>>
    >>>> A consultant suggests that for all LUNs in the same RAID Group should

    > be
    >>>> assigned to the same SP. Is it sensible ?
    >>>>
    >>>> Regards,
    >>>> Peter
    >>>>
    >>>> "Edwin vMierlo" wrote in

    > message
    >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >>>>> I would agree with JM, however one small remark to further specify for

    > a
    >>>>> CX;
    >>>>>
    >>>>> if one LUN is owned by one SP and the next LUN is owned by the other
    >>>>> SP,
    >>>>> than IO will be processed by both SP's
    >>>>> (at least that is my experience with CX)
    >>>>>
    >>>>> Not sure if this fully classify as an Active/Active as JM describes,
    >>>>> but
    >>>>> by
    >>>>> spreading LUNs accross the SPs you will get the benifit of both SP's
    >>>>> processing IO.
    >>>>>
    >>>>>
    >>>>>
    >>>>> "JM" wrote in message
    >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >>>>>> Peter wrote:
    >>>>>>> Dear JM,
    >>>>>>>
    >>>>>>> Many thanks for your advice.
    >>>>>>>
    >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    >>>>> Passive
    >>>>>>> array ?
    >>>>>>>
    >>>>>>> Regards,
    >>>>>>> Peter
    >>>>>> By my definition, any EMC Clariion is going to be an active /

    > passive
    >>>>>> array. They may call it active / active, but like I said it's

    > really
    >>>>>> just two SPs which are active / passive partners for each other. If
    >>>>>> your host has one connection to each SP, it will only be able to

    > send
    >>> IO
    >>>>>> down the path to the SP which owns each individual LUN. Typically

    > you
    >>>>>> would install EMC's PowerPath software to help the host understand

    > how
    >>>>>> to manage the multiple paths back to the Clariion.
    >>>>>
    >>>>
    >>>

    >>

    >
    >


  12. Re: What is Active / Active Array ?

    That could explain it, I have no experience with CX series with ATA drives,
    only FC drives.

    thanks for explaingin JM !
    rgds,
    Edwin.


    "JM" wrote in message
    news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >
    > I have heard this, but it only applies to ATA disks and not for Fibre
    > Channel disks in Clariion arrays. The way it was explained to me was
    > that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    > Fibre Channel RAID group, each disk essentially has a connection to each
    > SP, so the link control card (LCC) in the disk array enclosure (DAE) can
    > simply pass on commands to each individual disk. In an ATA DAE, the
    > LCCs are actually called BCCs* (I don't recall what the "B" stands for,
    > I've also heard BCCs called "paddle cards"). The BCCs incur some
    > overhead when commands come from different SPs which are bound for the
    > same disk. It has to flip-flop back and forth and dump them to the
    > single ported ATA disk. This may not be technically accurate but it's
    > the way I remember it being explained.
    >
    > The rule of thumb I've heard is that all LUNs in an ATA RAID group
    > should be owned by a single SP. For a Fibre Channel RAID group it
    > doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    > trespass and simply being forgetful we currently don't obey this rule to
    > the letter. Where we've mixed and matched LUN ownership in ATA RAID
    > groups we have yet to see any problems, performance or otherwise.
    >
    > * Early incarnations of Clariion ATA DAEs had many problems with the
    > firmware on these BCC cards, which is called FRUMON code. I had more
    > than one 20 hour day thanks to these things around the FLARE 13 days.
    > They seem to have worked out the kinks since then, we've been extremely
    > stable on ATA since about FLARE 16.
    >
    > Edwin vMierlo wrote:
    > > "he says that it is EMC's advice"
    > >
    > > well... he better back that up with a technical article from EMC
    > >
    > > or you need to talk to EMC directly, because I have never heard that,

    and I
    > > have some experience with different models in the CX-series.
    > >
    > >
    > >
    > >
    > >
    > > "Peter" wrote in message
    > > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    > >> Dear Edwin,
    > >>
    > >> I hold the same opinion as yours. I have asked him and he says that it

    is
    > >> EMC's advice. However, I have searched PowerLink but there is no

    article
    > >> mentioning it.
    > >>
    > >> Besides, if I choose auto assign, the first LUN in the same RAID group
    > >> created will choose SPA, the second one choose SPB, the third one

    choose
    > > SPA
    > >> that is different from what he says.
    > >>
    > >> Peter
    > >>
    > >>
    > >>
    > >> "Edwin vMierlo" wrote in

    message
    > >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > >>> You do not have to assign them to the same SP
    > >>> I would recommend that you spread your LUNs over the two SP's, to

    ensure
    > >>> both SP's are processing IO
    > >>>
    > >>> being in the same RAID group has nothing to do with which SP owns the

    > > LUN
    > >>> (from experience)
    > >>>
    > >>> unless the application or configuration is specific, and there are

    good
    > >>> technical reasons (which we cannot see in small posts in the

    newsgroups)
    > >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup to

    the
    > >>> same
    > >>> SP.
    > >>>
    > >>> Ask the consultant: why all luns in the same raidgroup to the same sp

    ?
    > >>> being a consultant, he/she must back up suggestions with technical
    > >>> reasons... (right ?)
    > >>>
    > >>> HTH,
    > >>> _Edwin.
    > >>>
    > >>> "Peter" wrote in message
    > >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > >>>> Dear JM and Edwin,
    > >>>>
    > >>>> Thank you for your advice.
    > >>>>
    > >>>> A consultant suggests that for all LUNs in the same RAID Group should

    > > be
    > >>>> assigned to the same SP. Is it sensible ?
    > >>>>
    > >>>> Regards,
    > >>>> Peter
    > >>>>
    > >>>> "Edwin vMierlo" wrote in

    > > message
    > >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >>>>> I would agree with JM, however one small remark to further specify

    for
    > > a
    > >>>>> CX;
    > >>>>>
    > >>>>> if one LUN is owned by one SP and the next LUN is owned by the other
    > >>>>> SP,
    > >>>>> than IO will be processed by both SP's
    > >>>>> (at least that is my experience with CX)
    > >>>>>
    > >>>>> Not sure if this fully classify as an Active/Active as JM describes,
    > >>>>> but
    > >>>>> by
    > >>>>> spreading LUNs accross the SPs you will get the benifit of both SP's
    > >>>>> processing IO.
    > >>>>>
    > >>>>>
    > >>>>>
    > >>>>> "JM" wrote in message
    > >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >>>>>> Peter wrote:
    > >>>>>>> Dear JM,
    > >>>>>>>
    > >>>>>>> Many thanks for your advice.
    > >>>>>>>
    > >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    > >>>>> Passive
    > >>>>>>> array ?
    > >>>>>>>
    > >>>>>>> Regards,
    > >>>>>>> Peter
    > >>>>>> By my definition, any EMC Clariion is going to be an active /

    > > passive
    > >>>>>> array. They may call it active / active, but like I said it's

    > > really
    > >>>>>> just two SPs which are active / passive partners for each other.

    If
    > >>>>>> your host has one connection to each SP, it will only be able to

    > > send
    > >>> IO
    > >>>>>> down the path to the SP which owns each individual LUN. Typically

    > > you
    > >>>>>> would install EMC's PowerPath software to help the host understand

    > > how
    > >>>>>> to manage the multiple paths back to the Clariion.
    > >>>>>
    > >>>>
    > >>>
    > >>

    > >
    > >




  13. Re: What is Active / Active Array ?

    Dear JM and Edwin,

    Thank you for your advice.
    Since we are using FC disk and not ATA one, the consultant's advice looks
    not valid.

    Does ATA disk means SATA disk ?
    Can we use FC disk with different speed ? This is because from EMC web
    site, I find that they support SAN disk with higher rpm (Of course, 300GB HD
    is still not available).

    The consultant also suggests us to upgrade to the latest firmware (The one
    we are using is more than 2 years old). Is this suggestion valid ?

    Regards,
    Peter

    "Edwin vMierlo" wrote in message
    news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    > That could explain it, I have no experience with CX series with ATA
    > drives,
    > only FC drives.
    >
    > thanks for explaingin JM !
    > rgds,
    > Edwin.
    >
    >
    > "JM" wrote in message
    > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >>
    >> I have heard this, but it only applies to ATA disks and not for Fibre
    >> Channel disks in Clariion arrays. The way it was explained to me was
    >> that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    >> Fibre Channel RAID group, each disk essentially has a connection to each
    >> SP, so the link control card (LCC) in the disk array enclosure (DAE) can
    >> simply pass on commands to each individual disk. In an ATA DAE, the
    >> LCCs are actually called BCCs* (I don't recall what the "B" stands for,
    >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    >> overhead when commands come from different SPs which are bound for the
    >> same disk. It has to flip-flop back and forth and dump them to the
    >> single ported ATA disk. This may not be technically accurate but it's
    >> the way I remember it being explained.
    >>
    >> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    >> should be owned by a single SP. For a Fibre Channel RAID group it
    >> doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    >> trespass and simply being forgetful we currently don't obey this rule to
    >> the letter. Where we've mixed and matched LUN ownership in ATA RAID
    >> groups we have yet to see any problems, performance or otherwise.
    >>
    >> * Early incarnations of Clariion ATA DAEs had many problems with the
    >> firmware on these BCC cards, which is called FRUMON code. I had more
    >> than one 20 hour day thanks to these things around the FLARE 13 days.
    >> They seem to have worked out the kinks since then, we've been extremely
    >> stable on ATA since about FLARE 16.
    >>
    >> Edwin vMierlo wrote:
    >> > "he says that it is EMC's advice"
    >> >
    >> > well... he better back that up with a technical article from EMC
    >> >
    >> > or you need to talk to EMC directly, because I have never heard that,

    > and I
    >> > have some experience with different models in the CX-series.
    >> >
    >> >
    >> >
    >> >
    >> >
    >> > "Peter" wrote in message
    >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >> >> Dear Edwin,
    >> >>
    >> >> I hold the same opinion as yours. I have asked him and he says that
    >> >> it

    > is
    >> >> EMC's advice. However, I have searched PowerLink but there is no

    > article
    >> >> mentioning it.
    >> >>
    >> >> Besides, if I choose auto assign, the first LUN in the same RAID group
    >> >> created will choose SPA, the second one choose SPB, the third one

    > choose
    >> > SPA
    >> >> that is different from what he says.
    >> >>
    >> >> Peter
    >> >>
    >> >>
    >> >>
    >> >> "Edwin vMierlo" wrote in

    > message
    >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >> >>> You do not have to assign them to the same SP
    >> >>> I would recommend that you spread your LUNs over the two SP's, to

    > ensure
    >> >>> both SP's are processing IO
    >> >>>
    >> >>> being in the same RAID group has nothing to do with which SP owns the
    >> > LUN
    >> >>> (from experience)
    >> >>>
    >> >>> unless the application or configuration is specific, and there are

    > good
    >> >>> technical reasons (which we cannot see in small posts in the

    > newsgroups)
    >> >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup to

    > the
    >> >>> same
    >> >>> SP.
    >> >>>
    >> >>> Ask the consultant: why all luns in the same raidgroup to the same sp

    > ?
    >> >>> being a consultant, he/she must back up suggestions with technical
    >> >>> reasons... (right ?)
    >> >>>
    >> >>> HTH,
    >> >>> _Edwin.
    >> >>>
    >> >>> "Peter" wrote in message
    >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >> >>>> Dear JM and Edwin,
    >> >>>>
    >> >>>> Thank you for your advice.
    >> >>>>
    >> >>>> A consultant suggests that for all LUNs in the same RAID Group
    >> >>>> should
    >> > be
    >> >>>> assigned to the same SP. Is it sensible ?
    >> >>>>
    >> >>>> Regards,
    >> >>>> Peter
    >> >>>>
    >> >>>> "Edwin vMierlo" wrote in
    >> > message
    >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >> >>>>> I would agree with JM, however one small remark to further specify

    > for
    >> > a
    >> >>>>> CX;
    >> >>>>>
    >> >>>>> if one LUN is owned by one SP and the next LUN is owned by the
    >> >>>>> other
    >> >>>>> SP,
    >> >>>>> than IO will be processed by both SP's
    >> >>>>> (at least that is my experience with CX)
    >> >>>>>
    >> >>>>> Not sure if this fully classify as an Active/Active as JM
    >> >>>>> describes,
    >> >>>>> but
    >> >>>>> by
    >> >>>>> spreading LUNs accross the SPs you will get the benifit of both
    >> >>>>> SP's
    >> >>>>> processing IO.
    >> >>>>>
    >> >>>>>
    >> >>>>>
    >> >>>>> "JM" wrote in message
    >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> >>>>>> Peter wrote:
    >> >>>>>>> Dear JM,
    >> >>>>>>>
    >> >>>>>>> Many thanks for your advice.
    >> >>>>>>>
    >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    >> >>>>> Passive
    >> >>>>>>> array ?
    >> >>>>>>>
    >> >>>>>>> Regards,
    >> >>>>>>> Peter
    >> >>>>>> By my definition, any EMC Clariion is going to be an active /
    >> > passive
    >> >>>>>> array. They may call it active / active, but like I said it's
    >> > really
    >> >>>>>> just two SPs which are active / passive partners for each other.

    > If
    >> >>>>>> your host has one connection to each SP, it will only be able to
    >> > send
    >> >>> IO
    >> >>>>>> down the path to the SP which owns each individual LUN. Typically
    >> > you
    >> >>>>>> would install EMC's PowerPath software to help the host understand
    >> > how
    >> >>>>>> to manage the multiple paths back to the Clariion.
    >> >>>>>
    >> >>>>
    >> >>>
    >> >>
    >> >
    >> >

    >
    >




  14. Re: What is Active / Active Array ?

    response in-line


    "Peter" wrote in message
    news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    > Dear JM and Edwin,
    >
    > Thank you for your advice.
    > Since we are using FC disk and not ATA one, the consultant's advice looks
    > not valid.
    >
    > Does ATA disk means SATA disk ?
    > Can we use FC disk with different speed ?


    This might be depending on the Flare-code revision, and other things, you
    really need to ask that question to your EMC rep.

    > This is because from EMC web
    > site, I find that they support SAN disk with higher rpm (Of course, 300GB

    HD
    > is still not available).
    >
    > The consultant also suggests us to upgrade to the latest firmware (The one
    > we are using is more than 2 years old). Is this suggestion valid ?


    Most of the time; yes. Keep abrest with latest versions of software and
    firmware. BUT If you have a test or try-out system, I would highly recommend
    to run upgrades on test systems first.

    >
    > Regards,
    > Peter
    >
    > "Edwin vMierlo" wrote in message
    > news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    > > That could explain it, I have no experience with CX series with ATA
    > > drives,
    > > only FC drives.
    > >
    > > thanks for explaingin JM !
    > > rgds,
    > > Edwin.
    > >
    > >
    > > "JM" wrote in message
    > > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    > >>
    > >> I have heard this, but it only applies to ATA disks and not for Fibre
    > >> Channel disks in Clariion arrays. The way it was explained to me was
    > >> that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    > >> Fibre Channel RAID group, each disk essentially has a connection to

    each
    > >> SP, so the link control card (LCC) in the disk array enclosure (DAE)

    can
    > >> simply pass on commands to each individual disk. In an ATA DAE, the
    > >> LCCs are actually called BCCs* (I don't recall what the "B" stands for,
    > >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    > >> overhead when commands come from different SPs which are bound for the
    > >> same disk. It has to flip-flop back and forth and dump them to the
    > >> single ported ATA disk. This may not be technically accurate but it's
    > >> the way I remember it being explained.
    > >>
    > >> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    > >> should be owned by a single SP. For a Fibre Channel RAID group it
    > >> doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    > >> trespass and simply being forgetful we currently don't obey this rule

    to
    > >> the letter. Where we've mixed and matched LUN ownership in ATA RAID
    > >> groups we have yet to see any problems, performance or otherwise.
    > >>
    > >> * Early incarnations of Clariion ATA DAEs had many problems with the
    > >> firmware on these BCC cards, which is called FRUMON code. I had more
    > >> than one 20 hour day thanks to these things around the FLARE 13 days.
    > >> They seem to have worked out the kinks since then, we've been extremely
    > >> stable on ATA since about FLARE 16.
    > >>
    > >> Edwin vMierlo wrote:
    > >> > "he says that it is EMC's advice"
    > >> >
    > >> > well... he better back that up with a technical article from EMC
    > >> >
    > >> > or you need to talk to EMC directly, because I have never heard that,

    > > and I
    > >> > have some experience with different models in the CX-series.
    > >> >
    > >> >
    > >> >
    > >> >
    > >> >
    > >> > "Peter" wrote in message
    > >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    > >> >> Dear Edwin,
    > >> >>
    > >> >> I hold the same opinion as yours. I have asked him and he says that
    > >> >> it

    > > is
    > >> >> EMC's advice. However, I have searched PowerLink but there is no

    > > article
    > >> >> mentioning it.
    > >> >>
    > >> >> Besides, if I choose auto assign, the first LUN in the same RAID

    group
    > >> >> created will choose SPA, the second one choose SPB, the third one

    > > choose
    > >> > SPA
    > >> >> that is different from what he says.
    > >> >>
    > >> >> Peter
    > >> >>
    > >> >>
    > >> >>
    > >> >> "Edwin vMierlo" wrote in

    > > message
    > >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > >> >>> You do not have to assign them to the same SP
    > >> >>> I would recommend that you spread your LUNs over the two SP's, to

    > > ensure
    > >> >>> both SP's are processing IO
    > >> >>>
    > >> >>> being in the same RAID group has nothing to do with which SP owns

    the
    > >> > LUN
    > >> >>> (from experience)
    > >> >>>
    > >> >>> unless the application or configuration is specific, and there are

    > > good
    > >> >>> technical reasons (which we cannot see in small posts in the

    > > newsgroups)
    > >> >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup to

    > > the
    > >> >>> same
    > >> >>> SP.
    > >> >>>
    > >> >>> Ask the consultant: why all luns in the same raidgroup to the same

    sp
    > > ?
    > >> >>> being a consultant, he/she must back up suggestions with technical
    > >> >>> reasons... (right ?)
    > >> >>>
    > >> >>> HTH,
    > >> >>> _Edwin.
    > >> >>>
    > >> >>> "Peter" wrote in message
    > >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > >> >>>> Dear JM and Edwin,
    > >> >>>>
    > >> >>>> Thank you for your advice.
    > >> >>>>
    > >> >>>> A consultant suggests that for all LUNs in the same RAID Group
    > >> >>>> should
    > >> > be
    > >> >>>> assigned to the same SP. Is it sensible ?
    > >> >>>>
    > >> >>>> Regards,
    > >> >>>> Peter
    > >> >>>>
    > >> >>>> "Edwin vMierlo" wrote in
    > >> > message
    > >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >> >>>>> I would agree with JM, however one small remark to further

    specify
    > > for
    > >> > a
    > >> >>>>> CX;
    > >> >>>>>
    > >> >>>>> if one LUN is owned by one SP and the next LUN is owned by the
    > >> >>>>> other
    > >> >>>>> SP,
    > >> >>>>> than IO will be processed by both SP's
    > >> >>>>> (at least that is my experience with CX)
    > >> >>>>>
    > >> >>>>> Not sure if this fully classify as an Active/Active as JM
    > >> >>>>> describes,
    > >> >>>>> but
    > >> >>>>> by
    > >> >>>>> spreading LUNs accross the SPs you will get the benifit of both
    > >> >>>>> SP's
    > >> >>>>> processing IO.
    > >> >>>>>
    > >> >>>>>
    > >> >>>>>
    > >> >>>>> "JM" wrote in message
    > >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >> >>>>>> Peter wrote:
    > >> >>>>>>> Dear JM,
    > >> >>>>>>>
    > >> >>>>>>> Many thanks for your advice.
    > >> >>>>>>>
    > >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active

    /
    > >> >>>>> Passive
    > >> >>>>>>> array ?
    > >> >>>>>>>
    > >> >>>>>>> Regards,
    > >> >>>>>>> Peter
    > >> >>>>>> By my definition, any EMC Clariion is going to be an active /
    > >> > passive
    > >> >>>>>> array. They may call it active / active, but like I said it's
    > >> > really
    > >> >>>>>> just two SPs which are active / passive partners for each other.

    > > If
    > >> >>>>>> your host has one connection to each SP, it will only be able to
    > >> > send
    > >> >>> IO
    > >> >>>>>> down the path to the SP which owns each individual LUN.

    Typically
    > >> > you
    > >> >>>>>> would install EMC's PowerPath software to help the host

    understand
    > >> > how
    > >> >>>>>> to manage the multiple paths back to the Clariion.
    > >> >>>>>
    > >> >>>>
    > >> >>>
    > >> >>
    > >> >
    > >> >

    > >
    > >

    >
    >




  15. Re: What is Active / Active Array ?


    Actually, I don't believe Clariions ever used SATA disks. They are all
    parallel ATA, PATA. Either way, you can probably think about them as
    the same thing for the purpose of this conversation. The newest
    Clariions, the CX3 line, use what EMC is calling LCFC drives, or "low
    cost Fibre Channel". I think it's the same technology that HP has been
    using for a while under the name FATA (Fiber ATA). They've skipped the
    SATA interface all together. Anyhow, kind of a moot point for you since
    you're using all Fibre Channel disks.

    You can use disks of different speeds (10k vs 15k rpm) in the same
    Clariion. I'm pretty sure you can even run both speeds in the same DAE,
    but I'm not positive on that one. As far as upgrading to the latest
    firmware, EMC always has a "go-to" code level that they want everyone to
    be at. In the past three years I don't believe any code upgrades we've
    done introduced new problems, but they've definitely solved existing
    problems. We've been running FLARE 19 for quite a while on a number of
    CX700 and CX500s without problems. I'd be inclined to agree with your
    consultant on the firmware upgrade.

    Peter wrote:
    > Dear JM and Edwin,
    >
    > Thank you for your advice.
    > Since we are using FC disk and not ATA one, the consultant's advice looks
    > not valid.
    >
    > Does ATA disk means SATA disk ?
    > Can we use FC disk with different speed ? This is because from EMC web
    > site, I find that they support SAN disk with higher rpm (Of course, 300GB HD
    > is still not available).
    >
    > The consultant also suggests us to upgrade to the latest firmware (The one
    > we are using is more than 2 years old). Is this suggestion valid ?
    >
    > Regards,
    > Peter
    >
    > "Edwin vMierlo" wrote in message
    > news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    >> That could explain it, I have no experience with CX series with ATA
    >> drives,
    >> only FC drives.
    >>
    >> thanks for explaingin JM !
    >> rgds,
    >> Edwin.
    >>
    >>
    >> "JM" wrote in message
    >> news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >>> I have heard this, but it only applies to ATA disks and not for Fibre
    >>> Channel disks in Clariion arrays. The way it was explained to me was
    >>> that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    >>> Fibre Channel RAID group, each disk essentially has a connection to each
    >>> SP, so the link control card (LCC) in the disk array enclosure (DAE) can
    >>> simply pass on commands to each individual disk. In an ATA DAE, the
    >>> LCCs are actually called BCCs* (I don't recall what the "B" stands for,
    >>> I've also heard BCCs called "paddle cards"). The BCCs incur some
    >>> overhead when commands come from different SPs which are bound for the
    >>> same disk. It has to flip-flop back and forth and dump them to the
    >>> single ported ATA disk. This may not be technically accurate but it's
    >>> the way I remember it being explained.
    >>>
    >>> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    >>> should be owned by a single SP. For a Fibre Channel RAID group it
    >>> doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    >>> trespass and simply being forgetful we currently don't obey this rule to
    >>> the letter. Where we've mixed and matched LUN ownership in ATA RAID
    >>> groups we have yet to see any problems, performance or otherwise.
    >>>
    >>> * Early incarnations of Clariion ATA DAEs had many problems with the
    >>> firmware on these BCC cards, which is called FRUMON code. I had more
    >>> than one 20 hour day thanks to these things around the FLARE 13 days.
    >>> They seem to have worked out the kinks since then, we've been extremely
    >>> stable on ATA since about FLARE 16.
    >>>
    >>> Edwin vMierlo wrote:
    >>>> "he says that it is EMC's advice"
    >>>>
    >>>> well... he better back that up with a technical article from EMC
    >>>>
    >>>> or you need to talk to EMC directly, because I have never heard that,

    >> and I
    >>>> have some experience with different models in the CX-series.
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>> "Peter" wrote in message
    >>>> news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >>>>> Dear Edwin,
    >>>>>
    >>>>> I hold the same opinion as yours. I have asked him and he says that
    >>>>> it

    >> is
    >>>>> EMC's advice. However, I have searched PowerLink but there is no

    >> article
    >>>>> mentioning it.
    >>>>>
    >>>>> Besides, if I choose auto assign, the first LUN in the same RAID group
    >>>>> created will choose SPA, the second one choose SPB, the third one

    >> choose
    >>>> SPA
    >>>>> that is different from what he says.
    >>>>>
    >>>>> Peter
    >>>>>
    >>>>>
    >>>>>
    >>>>> "Edwin vMierlo" wrote in

    >> message
    >>>>> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >>>>>> You do not have to assign them to the same SP
    >>>>>> I would recommend that you spread your LUNs over the two SP's, to

    >> ensure
    >>>>>> both SP's are processing IO
    >>>>>>
    >>>>>> being in the same RAID group has nothing to do with which SP owns the
    >>>> LUN
    >>>>>> (from experience)
    >>>>>>
    >>>>>> unless the application or configuration is specific, and there are

    >> good
    >>>>>> technical reasons (which we cannot see in small posts in the

    >> newsgroups)
    >>>>>> then there _might_ be a reason to assign all LUNs in a RAIDgroup to

    >> the
    >>>>>> same
    >>>>>> SP.
    >>>>>>
    >>>>>> Ask the consultant: why all luns in the same raidgroup to the same sp

    >> ?
    >>>>>> being a consultant, he/she must back up suggestions with technical
    >>>>>> reasons... (right ?)
    >>>>>>
    >>>>>> HTH,
    >>>>>> _Edwin.
    >>>>>>
    >>>>>> "Peter" wrote in message
    >>>>>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >>>>>>> Dear JM and Edwin,
    >>>>>>>
    >>>>>>> Thank you for your advice.
    >>>>>>>
    >>>>>>> A consultant suggests that for all LUNs in the same RAID Group
    >>>>>>> should
    >>>> be
    >>>>>>> assigned to the same SP. Is it sensible ?
    >>>>>>>
    >>>>>>> Regards,
    >>>>>>> Peter
    >>>>>>>
    >>>>>>> "Edwin vMierlo" wrote in
    >>>> message
    >>>>>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >>>>>>>> I would agree with JM, however one small remark to further specify

    >> for
    >>>> a
    >>>>>>>> CX;
    >>>>>>>>
    >>>>>>>> if one LUN is owned by one SP and the next LUN is owned by the
    >>>>>>>> other
    >>>>>>>> SP,
    >>>>>>>> than IO will be processed by both SP's
    >>>>>>>> (at least that is my experience with CX)
    >>>>>>>>
    >>>>>>>> Not sure if this fully classify as an Active/Active as JM
    >>>>>>>> describes,
    >>>>>>>> but
    >>>>>>>> by
    >>>>>>>> spreading LUNs accross the SPs you will get the benifit of both
    >>>>>>>> SP's
    >>>>>>>> processing IO.
    >>>>>>>>
    >>>>>>>>
    >>>>>>>>
    >>>>>>>> "JM" wrote in message
    >>>>>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >>>>>>>>> Peter wrote:
    >>>>>>>>>> Dear JM,
    >>>>>>>>>>
    >>>>>>>>>> Many thanks for your advice.
    >>>>>>>>>>
    >>>>>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an Active /
    >>>>>>>> Passive
    >>>>>>>>>> array ?
    >>>>>>>>>>
    >>>>>>>>>> Regards,
    >>>>>>>>>> Peter
    >>>>>>>>> By my definition, any EMC Clariion is going to be an active /
    >>>> passive
    >>>>>>>>> array. They may call it active / active, but like I said it's
    >>>> really
    >>>>>>>>> just two SPs which are active / passive partners for each other.

    >> If
    >>>>>>>>> your host has one connection to each SP, it will only be able to
    >>>> send
    >>>>>> IO
    >>>>>>>>> down the path to the SP which owns each individual LUN. Typically
    >>>> you
    >>>>>>>>> would install EMC's PowerPath software to help the host understand
    >>>> how
    >>>>>>>>> to manage the multiple paths back to the Clariion.
    >>>>

    >>

    >
    >


  16. Re: What is Active / Active Array ?

    Dear Edwin and JM,

    DELL Engineer has updated the SAN Firmware and Hosts HBA / Navisphere and
    Powerpath for us during the weekend.

    However, from Navisphere web interface, we find that the Navisphere Agent in
    one of the host (Windows 2003 Server) cannot be retrieved by the Array. I
    would like to what will be the consequence ? Is it a serious problem or
    just the drives information is not presented ?

    I have checked Powerpath and it seems to be OK.

    Regards,
    Peter
    "Edwin vMierlo" wrote in message
    news:ONtpYYeGHHA.3952@TK2MSFTNGP02.phx.gbl...
    > response in-line
    >
    >
    > "Peter" wrote in message
    > news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    >> Dear JM and Edwin,
    >>
    >> Thank you for your advice.
    >> Since we are using FC disk and not ATA one, the consultant's advice looks
    >> not valid.
    >>
    >> Does ATA disk means SATA disk ?
    >> Can we use FC disk with different speed ?

    >
    > This might be depending on the Flare-code revision, and other things, you
    > really need to ask that question to your EMC rep.
    >
    >> This is because from EMC web
    >> site, I find that they support SAN disk with higher rpm (Of course, 300GB

    > HD
    >> is still not available).
    >>
    >> The consultant also suggests us to upgrade to the latest firmware (The
    >> one
    >> we are using is more than 2 years old). Is this suggestion valid ?

    >
    > Most of the time; yes. Keep abrest with latest versions of software and
    > firmware. BUT If you have a test or try-out system, I would highly
    > recommend
    > to run upgrades on test systems first.
    >
    >>
    >> Regards,
    >> Peter
    >>
    >> "Edwin vMierlo" wrote in message
    >> news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    >> > That could explain it, I have no experience with CX series with ATA
    >> > drives,
    >> > only FC drives.
    >> >
    >> > thanks for explaingin JM !
    >> > rgds,
    >> > Edwin.
    >> >
    >> >
    >> > "JM" wrote in message
    >> > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >> >>
    >> >> I have heard this, but it only applies to ATA disks and not for Fibre
    >> >> Channel disks in Clariion arrays. The way it was explained to me was
    >> >> that unlike Fibre Channel disks, ATA disks are not dual ported. For a
    >> >> Fibre Channel RAID group, each disk essentially has a connection to

    > each
    >> >> SP, so the link control card (LCC) in the disk array enclosure (DAE)

    > can
    >> >> simply pass on commands to each individual disk. In an ATA DAE, the
    >> >> LCCs are actually called BCCs* (I don't recall what the "B" stands
    >> >> for,
    >> >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    >> >> overhead when commands come from different SPs which are bound for the
    >> >> same disk. It has to flip-flop back and forth and dump them to the
    >> >> single ported ATA disk. This may not be technically accurate but it's
    >> >> the way I remember it being explained.
    >> >>
    >> >> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    >> >> should be owned by a single SP. For a Fibre Channel RAID group it
    >> >> doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    >> >> trespass and simply being forgetful we currently don't obey this rule

    > to
    >> >> the letter. Where we've mixed and matched LUN ownership in ATA RAID
    >> >> groups we have yet to see any problems, performance or otherwise.
    >> >>
    >> >> * Early incarnations of Clariion ATA DAEs had many problems with the
    >> >> firmware on these BCC cards, which is called FRUMON code. I had more
    >> >> than one 20 hour day thanks to these things around the FLARE 13 days.
    >> >> They seem to have worked out the kinks since then, we've been
    >> >> extremely
    >> >> stable on ATA since about FLARE 16.
    >> >>
    >> >> Edwin vMierlo wrote:
    >> >> > "he says that it is EMC's advice"
    >> >> >
    >> >> > well... he better back that up with a technical article from EMC
    >> >> >
    >> >> > or you need to talk to EMC directly, because I have never heard
    >> >> > that,
    >> > and I
    >> >> > have some experience with different models in the CX-series.
    >> >> >
    >> >> >
    >> >> >
    >> >> >
    >> >> >
    >> >> > "Peter" wrote in message
    >> >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >> >> >> Dear Edwin,
    >> >> >>
    >> >> >> I hold the same opinion as yours. I have asked him and he says
    >> >> >> that
    >> >> >> it
    >> > is
    >> >> >> EMC's advice. However, I have searched PowerLink but there is no
    >> > article
    >> >> >> mentioning it.
    >> >> >>
    >> >> >> Besides, if I choose auto assign, the first LUN in the same RAID

    > group
    >> >> >> created will choose SPA, the second one choose SPB, the third one
    >> > choose
    >> >> > SPA
    >> >> >> that is different from what he says.
    >> >> >>
    >> >> >> Peter
    >> >> >>
    >> >> >>
    >> >> >>
    >> >> >> "Edwin vMierlo" wrote in
    >> > message
    >> >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >> >> >>> You do not have to assign them to the same SP
    >> >> >>> I would recommend that you spread your LUNs over the two SP's, to
    >> > ensure
    >> >> >>> both SP's are processing IO
    >> >> >>>
    >> >> >>> being in the same RAID group has nothing to do with which SP owns

    > the
    >> >> > LUN
    >> >> >>> (from experience)
    >> >> >>>
    >> >> >>> unless the application or configuration is specific, and there are
    >> > good
    >> >> >>> technical reasons (which we cannot see in small posts in the
    >> > newsgroups)
    >> >> >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup
    >> >> >>> to
    >> > the
    >> >> >>> same
    >> >> >>> SP.
    >> >> >>>
    >> >> >>> Ask the consultant: why all luns in the same raidgroup to the same

    > sp
    >> > ?
    >> >> >>> being a consultant, he/she must back up suggestions with technical
    >> >> >>> reasons... (right ?)
    >> >> >>>
    >> >> >>> HTH,
    >> >> >>> _Edwin.
    >> >> >>>
    >> >> >>> "Peter" wrote in message
    >> >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >> >> >>>> Dear JM and Edwin,
    >> >> >>>>
    >> >> >>>> Thank you for your advice.
    >> >> >>>>
    >> >> >>>> A consultant suggests that for all LUNs in the same RAID Group
    >> >> >>>> should
    >> >> > be
    >> >> >>>> assigned to the same SP. Is it sensible ?
    >> >> >>>>
    >> >> >>>> Regards,
    >> >> >>>> Peter
    >> >> >>>>
    >> >> >>>> "Edwin vMierlo" wrote in
    >> >> > message
    >> >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >> >> >>>>> I would agree with JM, however one small remark to further

    > specify
    >> > for
    >> >> > a
    >> >> >>>>> CX;
    >> >> >>>>>
    >> >> >>>>> if one LUN is owned by one SP and the next LUN is owned by the
    >> >> >>>>> other
    >> >> >>>>> SP,
    >> >> >>>>> than IO will be processed by both SP's
    >> >> >>>>> (at least that is my experience with CX)
    >> >> >>>>>
    >> >> >>>>> Not sure if this fully classify as an Active/Active as JM
    >> >> >>>>> describes,
    >> >> >>>>> but
    >> >> >>>>> by
    >> >> >>>>> spreading LUNs accross the SPs you will get the benifit of both
    >> >> >>>>> SP's
    >> >> >>>>> processing IO.
    >> >> >>>>>
    >> >> >>>>>
    >> >> >>>>>
    >> >> >>>>> "JM" wrote in message
    >> >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> >> >>>>>> Peter wrote:
    >> >> >>>>>>> Dear JM,
    >> >> >>>>>>>
    >> >> >>>>>>> Many thanks for your advice.
    >> >> >>>>>>>
    >> >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an
    >> >> >>>>>>> Active

    > /
    >> >> >>>>> Passive
    >> >> >>>>>>> array ?
    >> >> >>>>>>>
    >> >> >>>>>>> Regards,
    >> >> >>>>>>> Peter
    >> >> >>>>>> By my definition, any EMC Clariion is going to be an active /
    >> >> > passive
    >> >> >>>>>> array. They may call it active / active, but like I said it's
    >> >> > really
    >> >> >>>>>> just two SPs which are active / passive partners for each
    >> >> >>>>>> other.
    >> > If
    >> >> >>>>>> your host has one connection to each SP, it will only be able
    >> >> >>>>>> to
    >> >> > send
    >> >> >>> IO
    >> >> >>>>>> down the path to the SP which owns each individual LUN.

    > Typically
    >> >> > you
    >> >> >>>>>> would install EMC's PowerPath software to help the host

    > understand
    >> >> > how
    >> >> >>>>>> to manage the multiple paths back to the Clariion.
    >> >> >>>>>
    >> >> >>>>
    >> >> >>>
    >> >> >>
    >> >> >
    >> >> >
    >> >
    >> >

    >>
    >>

    >
    >




  17. Re: What is Active / Active Array ?

    Peter,

    non-functioning of Navisphere Agent will not limit you accessing your disks,
    if your HBA's from the host are properly logged in and registered, and in
    the proper storage group, you host will be able access the disk.

    Q: can you access the disks from your host ?

    then in regards to non-functioning of the Agent, there are some security
    settings which need to match between host and array. Easiest is to open a
    case with EMC, they can talk you through this is 5 minutes. Alternatively,
    there is a connectivity guide on the EMC website which will detail all steps
    needed. I would like to talk you through it by newsgroup posts, but the
    procedure has too many variables to be 100% accurate.



    "Peter" wrote in message
    news:uJhuY5oHHHA.1264@TK2MSFTNGP03.phx.gbl...
    > Dear Edwin and JM,
    >
    > DELL Engineer has updated the SAN Firmware and Hosts HBA / Navisphere and
    > Powerpath for us during the weekend.
    >
    > However, from Navisphere web interface, we find that the Navisphere Agent

    in
    > one of the host (Windows 2003 Server) cannot be retrieved by the Array. I
    > would like to what will be the consequence ? Is it a serious problem or
    > just the drives information is not presented ?
    >
    > I have checked Powerpath and it seems to be OK.
    >
    > Regards,
    > Peter
    > "Edwin vMierlo" wrote in message
    > news:ONtpYYeGHHA.3952@TK2MSFTNGP02.phx.gbl...
    > > response in-line
    > >
    > >
    > > "Peter" wrote in message
    > > news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    > >> Dear JM and Edwin,
    > >>
    > >> Thank you for your advice.
    > >> Since we are using FC disk and not ATA one, the consultant's advice

    looks
    > >> not valid.
    > >>
    > >> Does ATA disk means SATA disk ?
    > >> Can we use FC disk with different speed ?

    > >
    > > This might be depending on the Flare-code revision, and other things,

    you
    > > really need to ask that question to your EMC rep.
    > >
    > >> This is because from EMC web
    > >> site, I find that they support SAN disk with higher rpm (Of course,

    300GB
    > > HD
    > >> is still not available).
    > >>
    > >> The consultant also suggests us to upgrade to the latest firmware (The
    > >> one
    > >> we are using is more than 2 years old). Is this suggestion valid ?

    > >
    > > Most of the time; yes. Keep abrest with latest versions of software and
    > > firmware. BUT If you have a test or try-out system, I would highly
    > > recommend
    > > to run upgrades on test systems first.
    > >
    > >>
    > >> Regards,
    > >> Peter
    > >>
    > >> "Edwin vMierlo" wrote in

    message
    > >> news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    > >> > That could explain it, I have no experience with CX series with ATA
    > >> > drives,
    > >> > only FC drives.
    > >> >
    > >> > thanks for explaingin JM !
    > >> > rgds,
    > >> > Edwin.
    > >> >
    > >> >
    > >> > "JM" wrote in message
    > >> > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    > >> >>
    > >> >> I have heard this, but it only applies to ATA disks and not for

    Fibre
    > >> >> Channel disks in Clariion arrays. The way it was explained to me

    was
    > >> >> that unlike Fibre Channel disks, ATA disks are not dual ported. For

    a
    > >> >> Fibre Channel RAID group, each disk essentially has a connection to

    > > each
    > >> >> SP, so the link control card (LCC) in the disk array enclosure (DAE)

    > > can
    > >> >> simply pass on commands to each individual disk. In an ATA DAE, the
    > >> >> LCCs are actually called BCCs* (I don't recall what the "B" stands
    > >> >> for,
    > >> >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    > >> >> overhead when commands come from different SPs which are bound for

    the
    > >> >> same disk. It has to flip-flop back and forth and dump them to the
    > >> >> single ported ATA disk. This may not be technically accurate but

    it's
    > >> >> the way I remember it being explained.
    > >> >>
    > >> >> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    > >> >> should be owned by a single SP. For a Fibre Channel RAID group it
    > >> >> doesn't matter, mix and match at will. Due to not-so-infrequent LUN
    > >> >> trespass and simply being forgetful we currently don't obey this

    rule
    > > to
    > >> >> the letter. Where we've mixed and matched LUN ownership in ATA RAID
    > >> >> groups we have yet to see any problems, performance or otherwise.
    > >> >>
    > >> >> * Early incarnations of Clariion ATA DAEs had many problems with the
    > >> >> firmware on these BCC cards, which is called FRUMON code. I had

    more
    > >> >> than one 20 hour day thanks to these things around the FLARE 13

    days.
    > >> >> They seem to have worked out the kinks since then, we've been
    > >> >> extremely
    > >> >> stable on ATA since about FLARE 16.
    > >> >>
    > >> >> Edwin vMierlo wrote:
    > >> >> > "he says that it is EMC's advice"
    > >> >> >
    > >> >> > well... he better back that up with a technical article from EMC
    > >> >> >
    > >> >> > or you need to talk to EMC directly, because I have never heard
    > >> >> > that,
    > >> > and I
    > >> >> > have some experience with different models in the CX-series.
    > >> >> >
    > >> >> >
    > >> >> >
    > >> >> >
    > >> >> >
    > >> >> > "Peter" wrote in message
    > >> >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    > >> >> >> Dear Edwin,
    > >> >> >>
    > >> >> >> I hold the same opinion as yours. I have asked him and he says
    > >> >> >> that
    > >> >> >> it
    > >> > is
    > >> >> >> EMC's advice. However, I have searched PowerLink but there is no
    > >> > article
    > >> >> >> mentioning it.
    > >> >> >>
    > >> >> >> Besides, if I choose auto assign, the first LUN in the same RAID

    > > group
    > >> >> >> created will choose SPA, the second one choose SPB, the third one
    > >> > choose
    > >> >> > SPA
    > >> >> >> that is different from what he says.
    > >> >> >>
    > >> >> >> Peter
    > >> >> >>
    > >> >> >>
    > >> >> >>
    > >> >> >> "Edwin vMierlo" wrote in
    > >> > message
    > >> >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > >> >> >>> You do not have to assign them to the same SP
    > >> >> >>> I would recommend that you spread your LUNs over the two SP's,

    to
    > >> > ensure
    > >> >> >>> both SP's are processing IO
    > >> >> >>>
    > >> >> >>> being in the same RAID group has nothing to do with which SP

    owns
    > > the
    > >> >> > LUN
    > >> >> >>> (from experience)
    > >> >> >>>
    > >> >> >>> unless the application or configuration is specific, and there

    are
    > >> > good
    > >> >> >>> technical reasons (which we cannot see in small posts in the
    > >> > newsgroups)
    > >> >> >>> then there _might_ be a reason to assign all LUNs in a RAIDgroup
    > >> >> >>> to
    > >> > the
    > >> >> >>> same
    > >> >> >>> SP.
    > >> >> >>>
    > >> >> >>> Ask the consultant: why all luns in the same raidgroup to the

    same
    > > sp
    > >> > ?
    > >> >> >>> being a consultant, he/she must back up suggestions with

    technical
    > >> >> >>> reasons... (right ?)
    > >> >> >>>
    > >> >> >>> HTH,
    > >> >> >>> _Edwin.
    > >> >> >>>
    > >> >> >>> "Peter" wrote in message
    > >> >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > >> >> >>>> Dear JM and Edwin,
    > >> >> >>>>
    > >> >> >>>> Thank you for your advice.
    > >> >> >>>>
    > >> >> >>>> A consultant suggests that for all LUNs in the same RAID Group
    > >> >> >>>> should
    > >> >> > be
    > >> >> >>>> assigned to the same SP. Is it sensible ?
    > >> >> >>>>
    > >> >> >>>> Regards,
    > >> >> >>>> Peter
    > >> >> >>>>
    > >> >> >>>> "Edwin vMierlo" wrote

    in
    > >> >> > message
    > >> >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >> >> >>>>> I would agree with JM, however one small remark to further

    > > specify
    > >> > for
    > >> >> > a
    > >> >> >>>>> CX;
    > >> >> >>>>>
    > >> >> >>>>> if one LUN is owned by one SP and the next LUN is owned by the
    > >> >> >>>>> other
    > >> >> >>>>> SP,
    > >> >> >>>>> than IO will be processed by both SP's
    > >> >> >>>>> (at least that is my experience with CX)
    > >> >> >>>>>
    > >> >> >>>>> Not sure if this fully classify as an Active/Active as JM
    > >> >> >>>>> describes,
    > >> >> >>>>> but
    > >> >> >>>>> by
    > >> >> >>>>> spreading LUNs accross the SPs you will get the benifit of

    both
    > >> >> >>>>> SP's
    > >> >> >>>>> processing IO.
    > >> >> >>>>>
    > >> >> >>>>>
    > >> >> >>>>>
    > >> >> >>>>> "JM" wrote in message
    > >> >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >> >> >>>>>> Peter wrote:
    > >> >> >>>>>>> Dear JM,
    > >> >> >>>>>>>
    > >> >> >>>>>>> Many thanks for your advice.
    > >> >> >>>>>>>
    > >> >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an
    > >> >> >>>>>>> Active

    > > /
    > >> >> >>>>> Passive
    > >> >> >>>>>>> array ?
    > >> >> >>>>>>>
    > >> >> >>>>>>> Regards,
    > >> >> >>>>>>> Peter
    > >> >> >>>>>> By my definition, any EMC Clariion is going to be an active /
    > >> >> > passive
    > >> >> >>>>>> array. They may call it active / active, but like I said

    it's
    > >> >> > really
    > >> >> >>>>>> just two SPs which are active / passive partners for each
    > >> >> >>>>>> other.
    > >> > If
    > >> >> >>>>>> your host has one connection to each SP, it will only be able
    > >> >> >>>>>> to
    > >> >> > send
    > >> >> >>> IO
    > >> >> >>>>>> down the path to the SP which owns each individual LUN.

    > > Typically
    > >> >> > you
    > >> >> >>>>>> would install EMC's PowerPath software to help the host

    > > understand
    > >> >> > how
    > >> >> >>>>>> to manage the multiple paths back to the Clariion.
    > >> >> >>>>>
    > >> >> >>>>
    > >> >> >>>
    > >> >> >>
    > >> >> >
    > >> >> >
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >




  18. Re: What is Active / Active Array ?

    Yes, the host can access the disks.

    Since we purchased the array from DELL, we are not able to talk to EMC
    support. We have to talk to DELL staff.

    Regards,
    Peter

    "Edwin vMierlo" wrote in message
    news:OCcvyrpHHHA.420@TK2MSFTNGP06.phx.gbl...
    > Peter,
    >
    > non-functioning of Navisphere Agent will not limit you accessing your
    > disks,
    > if your HBA's from the host are properly logged in and registered, and in
    > the proper storage group, you host will be able access the disk.
    >
    > Q: can you access the disks from your host ?
    >
    > then in regards to non-functioning of the Agent, there are some security
    > settings which need to match between host and array. Easiest is to open a
    > case with EMC, they can talk you through this is 5 minutes. Alternatively,
    > there is a connectivity guide on the EMC website which will detail all
    > steps
    > needed. I would like to talk you through it by newsgroup posts, but the
    > procedure has too many variables to be 100% accurate.
    >
    >
    >
    > "Peter" wrote in message
    > news:uJhuY5oHHHA.1264@TK2MSFTNGP03.phx.gbl...
    >> Dear Edwin and JM,
    >>
    >> DELL Engineer has updated the SAN Firmware and Hosts HBA / Navisphere and
    >> Powerpath for us during the weekend.
    >>
    >> However, from Navisphere web interface, we find that the Navisphere Agent

    > in
    >> one of the host (Windows 2003 Server) cannot be retrieved by the Array.
    >> I
    >> would like to what will be the consequence ? Is it a serious problem or
    >> just the drives information is not presented ?
    >>
    >> I have checked Powerpath and it seems to be OK.
    >>
    >> Regards,
    >> Peter
    >> "Edwin vMierlo" wrote in message
    >> news:ONtpYYeGHHA.3952@TK2MSFTNGP02.phx.gbl...
    >> > response in-line
    >> >
    >> >
    >> > "Peter" wrote in message
    >> > news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    >> >> Dear JM and Edwin,
    >> >>
    >> >> Thank you for your advice.
    >> >> Since we are using FC disk and not ATA one, the consultant's advice

    > looks
    >> >> not valid.
    >> >>
    >> >> Does ATA disk means SATA disk ?
    >> >> Can we use FC disk with different speed ?
    >> >
    >> > This might be depending on the Flare-code revision, and other things,

    > you
    >> > really need to ask that question to your EMC rep.
    >> >
    >> >> This is because from EMC web
    >> >> site, I find that they support SAN disk with higher rpm (Of course,

    > 300GB
    >> > HD
    >> >> is still not available).
    >> >>
    >> >> The consultant also suggests us to upgrade to the latest firmware (The
    >> >> one
    >> >> we are using is more than 2 years old). Is this suggestion valid ?
    >> >
    >> > Most of the time; yes. Keep abrest with latest versions of software and
    >> > firmware. BUT If you have a test or try-out system, I would highly
    >> > recommend
    >> > to run upgrades on test systems first.
    >> >
    >> >>
    >> >> Regards,
    >> >> Peter
    >> >>
    >> >> "Edwin vMierlo" wrote in

    > message
    >> >> news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    >> >> > That could explain it, I have no experience with CX series with ATA
    >> >> > drives,
    >> >> > only FC drives.
    >> >> >
    >> >> > thanks for explaingin JM !
    >> >> > rgds,
    >> >> > Edwin.
    >> >> >
    >> >> >
    >> >> > "JM" wrote in message
    >> >> > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >> >> >>
    >> >> >> I have heard this, but it only applies to ATA disks and not for

    > Fibre
    >> >> >> Channel disks in Clariion arrays. The way it was explained to me

    > was
    >> >> >> that unlike Fibre Channel disks, ATA disks are not dual ported.
    >> >> >> For

    > a
    >> >> >> Fibre Channel RAID group, each disk essentially has a connection to
    >> > each
    >> >> >> SP, so the link control card (LCC) in the disk array enclosure
    >> >> >> (DAE)
    >> > can
    >> >> >> simply pass on commands to each individual disk. In an ATA DAE,
    >> >> >> the
    >> >> >> LCCs are actually called BCCs* (I don't recall what the "B" stands
    >> >> >> for,
    >> >> >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    >> >> >> overhead when commands come from different SPs which are bound for

    > the
    >> >> >> same disk. It has to flip-flop back and forth and dump them to the
    >> >> >> single ported ATA disk. This may not be technically accurate but

    > it's
    >> >> >> the way I remember it being explained.
    >> >> >>
    >> >> >> The rule of thumb I've heard is that all LUNs in an ATA RAID group
    >> >> >> should be owned by a single SP. For a Fibre Channel RAID group it
    >> >> >> doesn't matter, mix and match at will. Due to not-so-infrequent
    >> >> >> LUN
    >> >> >> trespass and simply being forgetful we currently don't obey this

    > rule
    >> > to
    >> >> >> the letter. Where we've mixed and matched LUN ownership in ATA
    >> >> >> RAID
    >> >> >> groups we have yet to see any problems, performance or otherwise.
    >> >> >>
    >> >> >> * Early incarnations of Clariion ATA DAEs had many problems with
    >> >> >> the
    >> >> >> firmware on these BCC cards, which is called FRUMON code. I had

    > more
    >> >> >> than one 20 hour day thanks to these things around the FLARE 13

    > days.
    >> >> >> They seem to have worked out the kinks since then, we've been
    >> >> >> extremely
    >> >> >> stable on ATA since about FLARE 16.
    >> >> >>
    >> >> >> Edwin vMierlo wrote:
    >> >> >> > "he says that it is EMC's advice"
    >> >> >> >
    >> >> >> > well... he better back that up with a technical article from EMC
    >> >> >> >
    >> >> >> > or you need to talk to EMC directly, because I have never heard
    >> >> >> > that,
    >> >> > and I
    >> >> >> > have some experience with different models in the CX-series.
    >> >> >> >
    >> >> >> >
    >> >> >> >
    >> >> >> >
    >> >> >> >
    >> >> >> > "Peter" wrote in message
    >> >> >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >> >> >> >> Dear Edwin,
    >> >> >> >>
    >> >> >> >> I hold the same opinion as yours. I have asked him and he says
    >> >> >> >> that
    >> >> >> >> it
    >> >> > is
    >> >> >> >> EMC's advice. However, I have searched PowerLink but there is
    >> >> >> >> no
    >> >> > article
    >> >> >> >> mentioning it.
    >> >> >> >>
    >> >> >> >> Besides, if I choose auto assign, the first LUN in the same RAID
    >> > group
    >> >> >> >> created will choose SPA, the second one choose SPB, the third
    >> >> >> >> one
    >> >> > choose
    >> >> >> > SPA
    >> >> >> >> that is different from what he says.
    >> >> >> >>
    >> >> >> >> Peter
    >> >> >> >>
    >> >> >> >>
    >> >> >> >>
    >> >> >> >> "Edwin vMierlo" wrote
    >> >> >> >> in
    >> >> > message
    >> >> >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >> >> >> >>> You do not have to assign them to the same SP
    >> >> >> >>> I would recommend that you spread your LUNs over the two SP's,

    > to
    >> >> > ensure
    >> >> >> >>> both SP's are processing IO
    >> >> >> >>>
    >> >> >> >>> being in the same RAID group has nothing to do with which SP

    > owns
    >> > the
    >> >> >> > LUN
    >> >> >> >>> (from experience)
    >> >> >> >>>
    >> >> >> >>> unless the application or configuration is specific, and there

    > are
    >> >> > good
    >> >> >> >>> technical reasons (which we cannot see in small posts in the
    >> >> > newsgroups)
    >> >> >> >>> then there _might_ be a reason to assign all LUNs in a
    >> >> >> >>> RAIDgroup
    >> >> >> >>> to
    >> >> > the
    >> >> >> >>> same
    >> >> >> >>> SP.
    >> >> >> >>>
    >> >> >> >>> Ask the consultant: why all luns in the same raidgroup to the

    > same
    >> > sp
    >> >> > ?
    >> >> >> >>> being a consultant, he/she must back up suggestions with

    > technical
    >> >> >> >>> reasons... (right ?)
    >> >> >> >>>
    >> >> >> >>> HTH,
    >> >> >> >>> _Edwin.
    >> >> >> >>>
    >> >> >> >>> "Peter" wrote in message
    >> >> >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >> >> >> >>>> Dear JM and Edwin,
    >> >> >> >>>>
    >> >> >> >>>> Thank you for your advice.
    >> >> >> >>>>
    >> >> >> >>>> A consultant suggests that for all LUNs in the same RAID Group
    >> >> >> >>>> should
    >> >> >> > be
    >> >> >> >>>> assigned to the same SP. Is it sensible ?
    >> >> >> >>>>
    >> >> >> >>>> Regards,
    >> >> >> >>>> Peter
    >> >> >> >>>>
    >> >> >> >>>> "Edwin vMierlo" wrote

    > in
    >> >> >> > message
    >> >> >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >> >> >> >>>>> I would agree with JM, however one small remark to further
    >> > specify
    >> >> > for
    >> >> >> > a
    >> >> >> >>>>> CX;
    >> >> >> >>>>>
    >> >> >> >>>>> if one LUN is owned by one SP and the next LUN is owned by
    >> >> >> >>>>> the
    >> >> >> >>>>> other
    >> >> >> >>>>> SP,
    >> >> >> >>>>> than IO will be processed by both SP's
    >> >> >> >>>>> (at least that is my experience with CX)
    >> >> >> >>>>>
    >> >> >> >>>>> Not sure if this fully classify as an Active/Active as JM
    >> >> >> >>>>> describes,
    >> >> >> >>>>> but
    >> >> >> >>>>> by
    >> >> >> >>>>> spreading LUNs accross the SPs you will get the benifit of

    > both
    >> >> >> >>>>> SP's
    >> >> >> >>>>> processing IO.
    >> >> >> >>>>>
    >> >> >> >>>>>
    >> >> >> >>>>>
    >> >> >> >>>>> "JM" wrote in message
    >> >> >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> >> >> >>>>>> Peter wrote:
    >> >> >> >>>>>>> Dear JM,
    >> >> >> >>>>>>>
    >> >> >> >>>>>>> Many thanks for your advice.
    >> >> >> >>>>>>>
    >> >> >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an
    >> >> >> >>>>>>> Active
    >> > /
    >> >> >> >>>>> Passive
    >> >> >> >>>>>>> array ?
    >> >> >> >>>>>>>
    >> >> >> >>>>>>> Regards,
    >> >> >> >>>>>>> Peter
    >> >> >> >>>>>> By my definition, any EMC Clariion is going to be an active
    >> >> >> >>>>>> /
    >> >> >> > passive
    >> >> >> >>>>>> array. They may call it active / active, but like I said

    > it's
    >> >> >> > really
    >> >> >> >>>>>> just two SPs which are active / passive partners for each
    >> >> >> >>>>>> other.
    >> >> > If
    >> >> >> >>>>>> your host has one connection to each SP, it will only be
    >> >> >> >>>>>> able
    >> >> >> >>>>>> to
    >> >> >> > send
    >> >> >> >>> IO
    >> >> >> >>>>>> down the path to the SP which owns each individual LUN.
    >> > Typically
    >> >> >> > you
    >> >> >> >>>>>> would install EMC's PowerPath software to help the host
    >> > understand
    >> >> >> > how
    >> >> >> >>>>>> to manage the multiple paths back to the Clariion.
    >> >> >> >>>>>
    >> >> >> >>>>
    >> >> >> >>>
    >> >> >> >>
    >> >> >> >
    >> >> >> >
    >> >> >
    >> >> >
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >




  19. Re: What is Active / Active Array ?

    They can talk to you the security setup as well (I guess, we only have EMC
    kit directly from EMC, I have no explicit experience dealing with Dell in
    this matter)

    Get the connectivity guide (from EMC)... ask the Dell boys to give you a
    (soft-)copy, it is a handy document explaining setups in general. You can
    base your internal setup and maintenance procedures on this doc.

    good luck,
    Edwin.


    "Peter" wrote in message
    news:urd80xpHHHA.3780@TK2MSFTNGP02.phx.gbl...
    > Yes, the host can access the disks.
    >
    > Since we purchased the array from DELL, we are not able to talk to EMC
    > support. We have to talk to DELL staff.
    >
    > Regards,
    > Peter
    >
    > "Edwin vMierlo" wrote in message
    > news:OCcvyrpHHHA.420@TK2MSFTNGP06.phx.gbl...
    > > Peter,
    > >
    > > non-functioning of Navisphere Agent will not limit you accessing your
    > > disks,
    > > if your HBA's from the host are properly logged in and registered, and

    in
    > > the proper storage group, you host will be able access the disk.
    > >
    > > Q: can you access the disks from your host ?
    > >
    > > then in regards to non-functioning of the Agent, there are some security
    > > settings which need to match between host and array. Easiest is to open

    a
    > > case with EMC, they can talk you through this is 5 minutes.

    Alternatively,
    > > there is a connectivity guide on the EMC website which will detail all
    > > steps
    > > needed. I would like to talk you through it by newsgroup posts, but the
    > > procedure has too many variables to be 100% accurate.
    > >
    > >
    > >
    > > "Peter" wrote in message
    > > news:uJhuY5oHHHA.1264@TK2MSFTNGP03.phx.gbl...
    > >> Dear Edwin and JM,
    > >>
    > >> DELL Engineer has updated the SAN Firmware and Hosts HBA / Navisphere

    and
    > >> Powerpath for us during the weekend.
    > >>
    > >> However, from Navisphere web interface, we find that the Navisphere

    Agent
    > > in
    > >> one of the host (Windows 2003 Server) cannot be retrieved by the Array.
    > >> I
    > >> would like to what will be the consequence ? Is it a serious problem

    or
    > >> just the drives information is not presented ?
    > >>
    > >> I have checked Powerpath and it seems to be OK.
    > >>
    > >> Regards,
    > >> Peter
    > >> "Edwin vMierlo" wrote in

    message
    > >> news:ONtpYYeGHHA.3952@TK2MSFTNGP02.phx.gbl...
    > >> > response in-line
    > >> >
    > >> >
    > >> > "Peter" wrote in message
    > >> > news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    > >> >> Dear JM and Edwin,
    > >> >>
    > >> >> Thank you for your advice.
    > >> >> Since we are using FC disk and not ATA one, the consultant's advice

    > > looks
    > >> >> not valid.
    > >> >>
    > >> >> Does ATA disk means SATA disk ?
    > >> >> Can we use FC disk with different speed ?
    > >> >
    > >> > This might be depending on the Flare-code revision, and other things,

    > > you
    > >> > really need to ask that question to your EMC rep.
    > >> >
    > >> >> This is because from EMC web
    > >> >> site, I find that they support SAN disk with higher rpm (Of course,

    > > 300GB
    > >> > HD
    > >> >> is still not available).
    > >> >>
    > >> >> The consultant also suggests us to upgrade to the latest firmware

    (The
    > >> >> one
    > >> >> we are using is more than 2 years old). Is this suggestion valid ?
    > >> >
    > >> > Most of the time; yes. Keep abrest with latest versions of software

    and
    > >> > firmware. BUT If you have a test or try-out system, I would highly
    > >> > recommend
    > >> > to run upgrades on test systems first.
    > >> >
    > >> >>
    > >> >> Regards,
    > >> >> Peter
    > >> >>
    > >> >> "Edwin vMierlo" wrote in

    > > message
    > >> >> news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    > >> >> > That could explain it, I have no experience with CX series with

    ATA
    > >> >> > drives,
    > >> >> > only FC drives.
    > >> >> >
    > >> >> > thanks for explaingin JM !
    > >> >> > rgds,
    > >> >> > Edwin.
    > >> >> >
    > >> >> >
    > >> >> > "JM" wrote in message
    > >> >> > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    > >> >> >>
    > >> >> >> I have heard this, but it only applies to ATA disks and not for

    > > Fibre
    > >> >> >> Channel disks in Clariion arrays. The way it was explained to me

    > > was
    > >> >> >> that unlike Fibre Channel disks, ATA disks are not dual ported.
    > >> >> >> For

    > > a
    > >> >> >> Fibre Channel RAID group, each disk essentially has a connection

    to
    > >> > each
    > >> >> >> SP, so the link control card (LCC) in the disk array enclosure
    > >> >> >> (DAE)
    > >> > can
    > >> >> >> simply pass on commands to each individual disk. In an ATA DAE,
    > >> >> >> the
    > >> >> >> LCCs are actually called BCCs* (I don't recall what the "B"

    stands
    > >> >> >> for,
    > >> >> >> I've also heard BCCs called "paddle cards"). The BCCs incur some
    > >> >> >> overhead when commands come from different SPs which are bound

    for
    > > the
    > >> >> >> same disk. It has to flip-flop back and forth and dump them to

    the
    > >> >> >> single ported ATA disk. This may not be technically accurate but

    > > it's
    > >> >> >> the way I remember it being explained.
    > >> >> >>
    > >> >> >> The rule of thumb I've heard is that all LUNs in an ATA RAID

    group
    > >> >> >> should be owned by a single SP. For a Fibre Channel RAID group

    it
    > >> >> >> doesn't matter, mix and match at will. Due to not-so-infrequent
    > >> >> >> LUN
    > >> >> >> trespass and simply being forgetful we currently don't obey this

    > > rule
    > >> > to
    > >> >> >> the letter. Where we've mixed and matched LUN ownership in ATA
    > >> >> >> RAID
    > >> >> >> groups we have yet to see any problems, performance or otherwise.
    > >> >> >>
    > >> >> >> * Early incarnations of Clariion ATA DAEs had many problems with
    > >> >> >> the
    > >> >> >> firmware on these BCC cards, which is called FRUMON code. I had

    > > more
    > >> >> >> than one 20 hour day thanks to these things around the FLARE 13

    > > days.
    > >> >> >> They seem to have worked out the kinks since then, we've been
    > >> >> >> extremely
    > >> >> >> stable on ATA since about FLARE 16.
    > >> >> >>
    > >> >> >> Edwin vMierlo wrote:
    > >> >> >> > "he says that it is EMC's advice"
    > >> >> >> >
    > >> >> >> > well... he better back that up with a technical article from

    EMC
    > >> >> >> >
    > >> >> >> > or you need to talk to EMC directly, because I have never heard
    > >> >> >> > that,
    > >> >> > and I
    > >> >> >> > have some experience with different models in the CX-series.
    > >> >> >> >
    > >> >> >> >
    > >> >> >> >
    > >> >> >> >
    > >> >> >> >
    > >> >> >> > "Peter" wrote in message
    > >> >> >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    > >> >> >> >> Dear Edwin,
    > >> >> >> >>
    > >> >> >> >> I hold the same opinion as yours. I have asked him and he

    says
    > >> >> >> >> that
    > >> >> >> >> it
    > >> >> > is
    > >> >> >> >> EMC's advice. However, I have searched PowerLink but there is
    > >> >> >> >> no
    > >> >> > article
    > >> >> >> >> mentioning it.
    > >> >> >> >>
    > >> >> >> >> Besides, if I choose auto assign, the first LUN in the same

    RAID
    > >> > group
    > >> >> >> >> created will choose SPA, the second one choose SPB, the third
    > >> >> >> >> one
    > >> >> > choose
    > >> >> >> > SPA
    > >> >> >> >> that is different from what he says.
    > >> >> >> >>
    > >> >> >> >> Peter
    > >> >> >> >>
    > >> >> >> >>
    > >> >> >> >>
    > >> >> >> >> "Edwin vMierlo" wrote
    > >> >> >> >> in
    > >> >> > message
    > >> >> >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    > >> >> >> >>> You do not have to assign them to the same SP
    > >> >> >> >>> I would recommend that you spread your LUNs over the two

    SP's,
    > > to
    > >> >> > ensure
    > >> >> >> >>> both SP's are processing IO
    > >> >> >> >>>
    > >> >> >> >>> being in the same RAID group has nothing to do with which SP

    > > owns
    > >> > the
    > >> >> >> > LUN
    > >> >> >> >>> (from experience)
    > >> >> >> >>>
    > >> >> >> >>> unless the application or configuration is specific, and

    there
    > > are
    > >> >> > good
    > >> >> >> >>> technical reasons (which we cannot see in small posts in the
    > >> >> > newsgroups)
    > >> >> >> >>> then there _might_ be a reason to assign all LUNs in a
    > >> >> >> >>> RAIDgroup
    > >> >> >> >>> to
    > >> >> > the
    > >> >> >> >>> same
    > >> >> >> >>> SP.
    > >> >> >> >>>
    > >> >> >> >>> Ask the consultant: why all luns in the same raidgroup to the

    > > same
    > >> > sp
    > >> >> > ?
    > >> >> >> >>> being a consultant, he/she must back up suggestions with

    > > technical
    > >> >> >> >>> reasons... (right ?)
    > >> >> >> >>>
    > >> >> >> >>> HTH,
    > >> >> >> >>> _Edwin.
    > >> >> >> >>>
    > >> >> >> >>> "Peter" wrote in message
    > >> >> >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    > >> >> >> >>>> Dear JM and Edwin,
    > >> >> >> >>>>
    > >> >> >> >>>> Thank you for your advice.
    > >> >> >> >>>>
    > >> >> >> >>>> A consultant suggests that for all LUNs in the same RAID

    Group
    > >> >> >> >>>> should
    > >> >> >> > be
    > >> >> >> >>>> assigned to the same SP. Is it sensible ?
    > >> >> >> >>>>
    > >> >> >> >>>> Regards,
    > >> >> >> >>>> Peter
    > >> >> >> >>>>
    > >> >> >> >>>> "Edwin vMierlo"

    wrote
    > > in
    > >> >> >> > message
    > >> >> >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    > >> >> >> >>>>> I would agree with JM, however one small remark to further
    > >> > specify
    > >> >> > for
    > >> >> >> > a
    > >> >> >> >>>>> CX;
    > >> >> >> >>>>>
    > >> >> >> >>>>> if one LUN is owned by one SP and the next LUN is owned by
    > >> >> >> >>>>> the
    > >> >> >> >>>>> other
    > >> >> >> >>>>> SP,
    > >> >> >> >>>>> than IO will be processed by both SP's
    > >> >> >> >>>>> (at least that is my experience with CX)
    > >> >> >> >>>>>
    > >> >> >> >>>>> Not sure if this fully classify as an Active/Active as JM
    > >> >> >> >>>>> describes,
    > >> >> >> >>>>> but
    > >> >> >> >>>>> by
    > >> >> >> >>>>> spreading LUNs accross the SPs you will get the benifit of

    > > both
    > >> >> >> >>>>> SP's
    > >> >> >> >>>>> processing IO.
    > >> >> >> >>>>>
    > >> >> >> >>>>>
    > >> >> >> >>>>>
    > >> >> >> >>>>> "JM" wrote in message
    > >> >> >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    > >> >> >> >>>>>> Peter wrote:
    > >> >> >> >>>>>>> Dear JM,
    > >> >> >> >>>>>>>
    > >> >> >> >>>>>>> Many thanks for your advice.
    > >> >> >> >>>>>>>
    > >> >> >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an
    > >> >> >> >>>>>>> Active
    > >> > /
    > >> >> >> >>>>> Passive
    > >> >> >> >>>>>>> array ?
    > >> >> >> >>>>>>>
    > >> >> >> >>>>>>> Regards,
    > >> >> >> >>>>>>> Peter
    > >> >> >> >>>>>> By my definition, any EMC Clariion is going to be an

    active
    > >> >> >> >>>>>> /
    > >> >> >> > passive
    > >> >> >> >>>>>> array. They may call it active / active, but like I said

    > > it's
    > >> >> >> > really
    > >> >> >> >>>>>> just two SPs which are active / passive partners for each
    > >> >> >> >>>>>> other.
    > >> >> > If
    > >> >> >> >>>>>> your host has one connection to each SP, it will only be
    > >> >> >> >>>>>> able
    > >> >> >> >>>>>> to
    > >> >> >> > send
    > >> >> >> >>> IO
    > >> >> >> >>>>>> down the path to the SP which owns each individual LUN.
    > >> > Typically
    > >> >> >> > you
    > >> >> >> >>>>>> would install EMC's PowerPath software to help the host
    > >> > understand
    > >> >> >> > how
    > >> >> >> >>>>>> to manage the multiple paths back to the Clariion.
    > >> >> >> >>>>>
    > >> >> >> >>>>
    > >> >> >> >>>
    > >> >> >> >>
    > >> >> >> >
    > >> >> >> >
    > >> >> >
    > >> >> >
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >




  20. Re: What is Active / Active Array ?

    Besides, I would like to know whether Navisphere Agent affects PowerPath
    Failover software ?

    Peter

    "Edwin vMierlo" wrote in message
    news:eh3DV8pHHHA.1468@TK2MSFTNGP04.phx.gbl...
    > They can talk to you the security setup as well (I guess, we only have EMC
    > kit directly from EMC, I have no explicit experience dealing with Dell in
    > this matter)
    >
    > Get the connectivity guide (from EMC)... ask the Dell boys to give you a
    > (soft-)copy, it is a handy document explaining setups in general. You can
    > base your internal setup and maintenance procedures on this doc.
    >
    > good luck,
    > Edwin.
    >
    >
    > "Peter" wrote in message
    > news:urd80xpHHHA.3780@TK2MSFTNGP02.phx.gbl...
    >> Yes, the host can access the disks.
    >>
    >> Since we purchased the array from DELL, we are not able to talk to EMC
    >> support. We have to talk to DELL staff.
    >>
    >> Regards,
    >> Peter
    >>
    >> "Edwin vMierlo" wrote in message
    >> news:OCcvyrpHHHA.420@TK2MSFTNGP06.phx.gbl...
    >> > Peter,
    >> >
    >> > non-functioning of Navisphere Agent will not limit you accessing your
    >> > disks,
    >> > if your HBA's from the host are properly logged in and registered, and

    > in
    >> > the proper storage group, you host will be able access the disk.
    >> >
    >> > Q: can you access the disks from your host ?
    >> >
    >> > then in regards to non-functioning of the Agent, there are some
    >> > security
    >> > settings which need to match between host and array. Easiest is to open

    > a
    >> > case with EMC, they can talk you through this is 5 minutes.

    > Alternatively,
    >> > there is a connectivity guide on the EMC website which will detail all
    >> > steps
    >> > needed. I would like to talk you through it by newsgroup posts, but the
    >> > procedure has too many variables to be 100% accurate.
    >> >
    >> >
    >> >
    >> > "Peter" wrote in message
    >> > news:uJhuY5oHHHA.1264@TK2MSFTNGP03.phx.gbl...
    >> >> Dear Edwin and JM,
    >> >>
    >> >> DELL Engineer has updated the SAN Firmware and Hosts HBA / Navisphere

    > and
    >> >> Powerpath for us during the weekend.
    >> >>
    >> >> However, from Navisphere web interface, we find that the Navisphere

    > Agent
    >> > in
    >> >> one of the host (Windows 2003 Server) cannot be retrieved by the
    >> >> Array.
    >> >> I
    >> >> would like to what will be the consequence ? Is it a serious problem

    > or
    >> >> just the drives information is not presented ?
    >> >>
    >> >> I have checked Powerpath and it seems to be OK.
    >> >>
    >> >> Regards,
    >> >> Peter
    >> >> "Edwin vMierlo" wrote in

    > message
    >> >> news:ONtpYYeGHHA.3952@TK2MSFTNGP02.phx.gbl...
    >> >> > response in-line
    >> >> >
    >> >> >
    >> >> > "Peter" wrote in message
    >> >> > news:ObW4iHeGHHA.924@TK2MSFTNGP02.phx.gbl...
    >> >> >> Dear JM and Edwin,
    >> >> >>
    >> >> >> Thank you for your advice.
    >> >> >> Since we are using FC disk and not ATA one, the consultant's advice
    >> > looks
    >> >> >> not valid.
    >> >> >>
    >> >> >> Does ATA disk means SATA disk ?
    >> >> >> Can we use FC disk with different speed ?
    >> >> >
    >> >> > This might be depending on the Flare-code revision, and other
    >> >> > things,
    >> > you
    >> >> > really need to ask that question to your EMC rep.
    >> >> >
    >> >> >> This is because from EMC web
    >> >> >> site, I find that they support SAN disk with higher rpm (Of course,
    >> > 300GB
    >> >> > HD
    >> >> >> is still not available).
    >> >> >>
    >> >> >> The consultant also suggests us to upgrade to the latest firmware

    > (The
    >> >> >> one
    >> >> >> we are using is more than 2 years old). Is this suggestion valid ?
    >> >> >
    >> >> > Most of the time; yes. Keep abrest with latest versions of software

    > and
    >> >> > firmware. BUT If you have a test or try-out system, I would highly
    >> >> > recommend
    >> >> > to run upgrades on test systems first.
    >> >> >
    >> >> >>
    >> >> >> Regards,
    >> >> >> Peter
    >> >> >>
    >> >> >> "Edwin vMierlo" wrote in
    >> > message
    >> >> >> news:eup4p1cGHHA.1240@TK2MSFTNGP03.phx.gbl...
    >> >> >> > That could explain it, I have no experience with CX series with

    > ATA
    >> >> >> > drives,
    >> >> >> > only FC drives.
    >> >> >> >
    >> >> >> > thanks for explaingin JM !
    >> >> >> > rgds,
    >> >> >> > Edwin.
    >> >> >> >
    >> >> >> >
    >> >> >> > "JM" wrote in message
    >> >> >> > news:%23jOAPHVGHHA.1280@TK2MSFTNGP04.phx.gbl...
    >> >> >> >>
    >> >> >> >> I have heard this, but it only applies to ATA disks and not for
    >> > Fibre
    >> >> >> >> Channel disks in Clariion arrays. The way it was explained to
    >> >> >> >> me
    >> > was
    >> >> >> >> that unlike Fibre Channel disks, ATA disks are not dual ported.
    >> >> >> >> For
    >> > a
    >> >> >> >> Fibre Channel RAID group, each disk essentially has a connection

    > to
    >> >> > each
    >> >> >> >> SP, so the link control card (LCC) in the disk array enclosure
    >> >> >> >> (DAE)
    >> >> > can
    >> >> >> >> simply pass on commands to each individual disk. In an ATA DAE,
    >> >> >> >> the
    >> >> >> >> LCCs are actually called BCCs* (I don't recall what the "B"

    > stands
    >> >> >> >> for,
    >> >> >> >> I've also heard BCCs called "paddle cards"). The BCCs incur
    >> >> >> >> some
    >> >> >> >> overhead when commands come from different SPs which are bound

    > for
    >> > the
    >> >> >> >> same disk. It has to flip-flop back and forth and dump them to

    > the
    >> >> >> >> single ported ATA disk. This may not be technically accurate
    >> >> >> >> but
    >> > it's
    >> >> >> >> the way I remember it being explained.
    >> >> >> >>
    >> >> >> >> The rule of thumb I've heard is that all LUNs in an ATA RAID

    > group
    >> >> >> >> should be owned by a single SP. For a Fibre Channel RAID group

    > it
    >> >> >> >> doesn't matter, mix and match at will. Due to not-so-infrequent
    >> >> >> >> LUN
    >> >> >> >> trespass and simply being forgetful we currently don't obey this
    >> > rule
    >> >> > to
    >> >> >> >> the letter. Where we've mixed and matched LUN ownership in ATA
    >> >> >> >> RAID
    >> >> >> >> groups we have yet to see any problems, performance or
    >> >> >> >> otherwise.
    >> >> >> >>
    >> >> >> >> * Early incarnations of Clariion ATA DAEs had many problems with
    >> >> >> >> the
    >> >> >> >> firmware on these BCC cards, which is called FRUMON code. I had
    >> > more
    >> >> >> >> than one 20 hour day thanks to these things around the FLARE 13
    >> > days.
    >> >> >> >> They seem to have worked out the kinks since then, we've been
    >> >> >> >> extremely
    >> >> >> >> stable on ATA since about FLARE 16.
    >> >> >> >>
    >> >> >> >> Edwin vMierlo wrote:
    >> >> >> >> > "he says that it is EMC's advice"
    >> >> >> >> >
    >> >> >> >> > well... he better back that up with a technical article from

    > EMC
    >> >> >> >> >
    >> >> >> >> > or you need to talk to EMC directly, because I have never
    >> >> >> >> > heard
    >> >> >> >> > that,
    >> >> >> > and I
    >> >> >> >> > have some experience with different models in the CX-series.
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> > "Peter" wrote in message
    >> >> >> >> > news:uK37JhRGHHA.4904@TK2MSFTNGP04.phx.gbl...
    >> >> >> >> >> Dear Edwin,
    >> >> >> >> >>
    >> >> >> >> >> I hold the same opinion as yours. I have asked him and he

    > says
    >> >> >> >> >> that
    >> >> >> >> >> it
    >> >> >> > is
    >> >> >> >> >> EMC's advice. However, I have searched PowerLink but there
    >> >> >> >> >> is
    >> >> >> >> >> no
    >> >> >> > article
    >> >> >> >> >> mentioning it.
    >> >> >> >> >>
    >> >> >> >> >> Besides, if I choose auto assign, the first LUN in the same

    > RAID
    >> >> > group
    >> >> >> >> >> created will choose SPA, the second one choose SPB, the third
    >> >> >> >> >> one
    >> >> >> > choose
    >> >> >> >> > SPA
    >> >> >> >> >> that is different from what he says.
    >> >> >> >> >>
    >> >> >> >> >> Peter
    >> >> >> >> >>
    >> >> >> >> >>
    >> >> >> >> >>
    >> >> >> >> >> "Edwin vMierlo"
    >> >> >> >> >> wrote
    >> >> >> >> >> in
    >> >> >> > message
    >> >> >> >> >> news:%23eoD1dRGHHA.3304@TK2MSFTNGP05.phx.gbl...
    >> >> >> >> >>> You do not have to assign them to the same SP
    >> >> >> >> >>> I would recommend that you spread your LUNs over the two

    > SP's,
    >> > to
    >> >> >> > ensure
    >> >> >> >> >>> both SP's are processing IO
    >> >> >> >> >>>
    >> >> >> >> >>> being in the same RAID group has nothing to do with which SP
    >> > owns
    >> >> > the
    >> >> >> >> > LUN
    >> >> >> >> >>> (from experience)
    >> >> >> >> >>>
    >> >> >> >> >>> unless the application or configuration is specific, and

    > there
    >> > are
    >> >> >> > good
    >> >> >> >> >>> technical reasons (which we cannot see in small posts in the
    >> >> >> > newsgroups)
    >> >> >> >> >>> then there _might_ be a reason to assign all LUNs in a
    >> >> >> >> >>> RAIDgroup
    >> >> >> >> >>> to
    >> >> >> > the
    >> >> >> >> >>> same
    >> >> >> >> >>> SP.
    >> >> >> >> >>>
    >> >> >> >> >>> Ask the consultant: why all luns in the same raidgroup to
    >> >> >> >> >>> the
    >> > same
    >> >> > sp
    >> >> >> > ?
    >> >> >> >> >>> being a consultant, he/she must back up suggestions with
    >> > technical
    >> >> >> >> >>> reasons... (right ?)
    >> >> >> >> >>>
    >> >> >> >> >>> HTH,
    >> >> >> >> >>> _Edwin.
    >> >> >> >> >>>
    >> >> >> >> >>> "Peter" wrote in message
    >> >> >> >> >>> news:%23eRCESRGHHA.1468@TK2MSFTNGP04.phx.gbl...
    >> >> >> >> >>>> Dear JM and Edwin,
    >> >> >> >> >>>>
    >> >> >> >> >>>> Thank you for your advice.
    >> >> >> >> >>>>
    >> >> >> >> >>>> A consultant suggests that for all LUNs in the same RAID

    > Group
    >> >> >> >> >>>> should
    >> >> >> >> > be
    >> >> >> >> >>>> assigned to the same SP. Is it sensible ?
    >> >> >> >> >>>>
    >> >> >> >> >>>> Regards,
    >> >> >> >> >>>> Peter
    >> >> >> >> >>>>
    >> >> >> >> >>>> "Edwin vMierlo"

    > wrote
    >> > in
    >> >> >> >> > message
    >> >> >> >> >>>> news:OSKVPSIGHHA.1784@TK2MSFTNGP06.phx.gbl...
    >> >> >> >> >>>>> I would agree with JM, however one small remark to further
    >> >> > specify
    >> >> >> > for
    >> >> >> >> > a
    >> >> >> >> >>>>> CX;
    >> >> >> >> >>>>>
    >> >> >> >> >>>>> if one LUN is owned by one SP and the next LUN is owned by
    >> >> >> >> >>>>> the
    >> >> >> >> >>>>> other
    >> >> >> >> >>>>> SP,
    >> >> >> >> >>>>> than IO will be processed by both SP's
    >> >> >> >> >>>>> (at least that is my experience with CX)
    >> >> >> >> >>>>>
    >> >> >> >> >>>>> Not sure if this fully classify as an Active/Active as JM
    >> >> >> >> >>>>> describes,
    >> >> >> >> >>>>> but
    >> >> >> >> >>>>> by
    >> >> >> >> >>>>> spreading LUNs accross the SPs you will get the benifit of
    >> > both
    >> >> >> >> >>>>> SP's
    >> >> >> >> >>>>> processing IO.
    >> >> >> >> >>>>>
    >> >> >> >> >>>>>
    >> >> >> >> >>>>>
    >> >> >> >> >>>>> "JM" wrote in message
    >> >> >> >> >>>>> news:%231WXTKIGHHA.1248@TK2MSFTNGP03.phx.gbl...
    >> >> >> >> >>>>>> Peter wrote:
    >> >> >> >> >>>>>>> Dear JM,
    >> >> >> >> >>>>>>>
    >> >> >> >> >>>>>>> Many thanks for your advice.
    >> >> >> >> >>>>>>>
    >> >> >> >> >>>>>>> We are using EMC CX300 SAN with 2 FC and 2 SP. Is it an
    >> >> >> >> >>>>>>> Active
    >> >> > /
    >> >> >> >> >>>>> Passive
    >> >> >> >> >>>>>>> array ?
    >> >> >> >> >>>>>>>
    >> >> >> >> >>>>>>> Regards,
    >> >> >> >> >>>>>>> Peter
    >> >> >> >> >>>>>> By my definition, any EMC Clariion is going to be an

    > active
    >> >> >> >> >>>>>> /
    >> >> >> >> > passive
    >> >> >> >> >>>>>> array. They may call it active / active, but like I said
    >> > it's
    >> >> >> >> > really
    >> >> >> >> >>>>>> just two SPs which are active / passive partners for each
    >> >> >> >> >>>>>> other.
    >> >> >> > If
    >> >> >> >> >>>>>> your host has one connection to each SP, it will only be
    >> >> >> >> >>>>>> able
    >> >> >> >> >>>>>> to
    >> >> >> >> > send
    >> >> >> >> >>> IO
    >> >> >> >> >>>>>> down the path to the SP which owns each individual LUN.
    >> >> > Typically
    >> >> >> >> > you
    >> >> >> >> >>>>>> would install EMC's PowerPath software to help the host
    >> >> > understand
    >> >> >> >> > how
    >> >> >> >> >>>>>> to manage the multiple paths back to the Clariion.
    >> >> >> >> >>>>>
    >> >> >> >> >>>>
    >> >> >> >> >>>
    >> >> >> >> >>
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >
    >> >> >> >
    >> >> >>
    >> >> >>
    >> >> >
    >> >> >
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >




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