How to make a mirror disk - SCO

This is a discussion on How to make a mirror disk - SCO ; Hello, We're running SCO Openserver Unix 5.0.5 on an IBM Netfinity 5000 server with 2 hot swappable disk drives. We don't have Raid. We're a small company. Everything is on drive 1 (data and system). Is there a way to ...

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Thread: How to make a mirror disk

  1. How to make a mirror disk

    Hello,

    We're running SCO Openserver Unix 5.0.5 on an IBM Netfinity 5000
    server with 2 hot swappable disk drives. We don't have Raid. We're a
    small company.

    Everything is on drive 1 (data and system). Is there a way to make
    drive 2 an absolute mirror of drive 1?

    In other words, after making the mirror drive, we would like to be
    able to pop drive 2 into slot 1, and be able to boot up as if nothing
    happened. Is such a scenario possible?

    If anybody provides this as a service, let us know. We might be
    willing to pay a modest amount for this service.

  2. Re: How to make a mirror disk

    JJ Jones wrote:
    > Hello,
    >
    > We're running SCO Openserver Unix 5.0.5 on an IBM Netfinity 5000
    > server with 2 hot swappable disk drives. We don't have Raid. We're a
    > small company.
    >
    > Everything is on drive 1 (data and system). Is there a way to make
    > drive 2 an absolute mirror of drive 1?
    >
    > In other words, after making the mirror drive, we would like to be
    > able to pop drive 2 into slot 1, and be able to boot up as if nothing
    > happened. Is such a scenario possible?
    >
    > If anybody provides this as a service, let us know. We might be
    > willing to pay a modest amount for this service.


    Hi, JJ.

    It has to be said - you do realize you are trusting your business to a
    machine that, in dog years, died two years ago, right?

    Not to mention a 12 year old version of SCO on top of it.

    How current is the patching on your SCO? There are tons of patches out
    for that version, some considered mandatory for security and stability
    reasons.

    I hope you are backing up regularly using one of the 'SuperTars' like
    Microlite's BackupEdge or Lone star's Lone-tar - standard tar or cpio
    backups can't do bit-level verifies and full disaster recovery like they
    can.

    Consider upgrading to an HP server - one of the ML or DL (rack mount)
    series especially. HP alone of the major hardware suppliers still
    supports SCO.

    You would have to upgrade the SCO to at least 5.0.7 or switch to Linux
    to drive the latest hardware (dual/quad core, SATA/SAS, Gigabit NIC's etc)

    As to your request - you *may* already have a hardware RAID controller
    in the machine, and it may already be setup to mirror your drives right now.

    Having a hot swap drive bay makes no sense unless you have hardware RAID.

    What does the machines BIOS show on boot? Does it briefly show an option
    to configure your hard drives, especially if it refers to a drive
    sub-system and invites you to hit to enter configuration mode?

    If so, hit and just look around. Do NOT make any changes to
    the current configuration, as some changes might wipe out data on both
    drives!

    A simple test - if you copy, say, a 20 MB file to another directory, do
    *both* drives lights flash? If so, you are already setup to do mirroring.

    As to using a software RAID solution - the license from SCO (if it's
    even available for 5.0.5 still) + the labor to set it up would probably
    wind up costing you as much as a new low end HP server with simple
    mirrored hardware SAS/SATA RAID 0.

    Feel free to call one of my numbers below and chat - new clients get up
    to 30 minute phone consults for no charge.

    Or just Email here with more specifics - you've found the right
    newsgroup to ask SCO related questions, lots of experienced people
    monitor this group.

    --
    ----------------------------------------------------
    Pat Welch, UBB Computer Services, a WCS Affiliate
    SCO Authorized Partner
    Microlite BackupEdge Certified Reseller
    Unix/Linux/Windows/Hardware Sales/Support
    (209) 745-1401 Cell: (209) 251-9120
    E-mail: patubb@inreach.com
    ----------------------------------------------------

  3. Re: How to make a mirror disk

    On Oct 21, 7:36 pm, JJ Jones wrote:
    > Hello,
    >
    > We're running SCO Openserver Unix 5.0.5 on an IBM Netfinity 5000
    > server with 2 hot swappable disk drives. We don't have Raid. We're a
    > small company.
    >
    > Everything is on drive 1 (data and system). Is there a way to make
    > drive 2 an absolute mirror of drive 1?
    >
    > In other words, after making the mirror drive, we would like to be
    > able to pop drive 2 into slot 1, and be able to boot up as if nothing
    > happened. Is such a scenario possible?
    >
    > If anybody provides this as a service, let us know. We might be
    > willing to pay a modest amount for this service.


    Follow up what Pat Welch said.
    If really necessary, use something like following syntax.
    dd if=/dev/rhd00 of=/dev/rhd10 conv=bmode bs=10240k
    it works well for me.

  4. Re: How to make a mirror disk

    JJ Jones wrote:
    > Hello,
    >
    > We're running SCO Openserver Unix 5.0.5 on an IBM Netfinity 5000
    > server with 2 hot swappable disk drives. We don't have Raid. We're a
    > small company.
    >
    > Everything is on drive 1 (data and system). Is there a way to make
    > drive 2 an absolute mirror of drive 1?
    >
    > In other words, after making the mirror drive, we would like to be
    > able to pop drive 2 into slot 1, and be able to boot up as if nothing
    > happened. Is such a scenario possible?
    >
    > If anybody provides this as a service, let us know. We might be
    > willing to pay a modest amount for this service.


    It depends. You don't want to mirror bad blocks, for example. But one thing
    you can do is shut down the system, use a Linux rescue or live CD, and simply
    run 'dd' between the drives.

    Another is to invest in some backup software such as 'Lone Tar', at
    http://www.LONE-TAR.com. This may serve your needs better, since it can also
    help you migrate it to another machine gracefully, and you can test it in advance.

    Are you looking to migrate off of it? At least update to OpenServer 5.0.7, if
    not dump SCO and hop to Solaris or Linux due to SCO's bankruptcy and
    demonstrated incompetence in court and refusal to play nice with open source
    development?

  5. Re: How to make a mirror disk



    On Tue, 21 Oct 2008, Pat Welch wrote:

    > JJ Jones wrote:
    >
    > Having a hot swap drive bay makes no sense unless you have hardware RAID.


    Is this a SCO thing? This is certainly not true for Linux Software RAID.


  6. Re: How to make a mirror disk


    ----- Original Message -----
    From: "JD"
    Newsgroups: comp.unix.sco.misc
    To:
    Sent: Wednesday, October 22, 2008 11:59 PM
    Subject: Re: How to make a mirror disk


    >
    >
    > On Tue, 21 Oct 2008, Pat Welch wrote:
    >
    >> JJ Jones wrote:
    >>
    >> Having a hot swap drive bay makes no sense unless you have hardware RAID.

    >
    > Is this a SCO thing? This is certainly not true for Linux Software RAID.


    There is no software raid for sco.
    (Actually, I think there might actually be some commercial
    software lvm out there for open server, like vertas or maybe
    something made by sco themselves, but I've never seen it or
    used it myself. I'm not sure if it quite qualifies as a raid
    implimentation, or if it supports hot adding/removing of
    physical disks. But even so lets continue on the assumption
    there is no software raid for open server.)

    The statement is mostly/usually, but still not quite true.
    Hot swap bays would still drastically reduce the time and the chance of
    scsi id/termination/etc jumper misconfig during drive replacement.

    It's true that normally, it's only via hardware raid and hot swap bays
    that you can totally avoid an on-site visit to swap a drive. You can
    often just mail a drive to the customer and someone there can pop it in.
    Normally, on SCO, without hardware raid, there is not many times when
    you would swap a drive and not need to be there yourself to do the
    formatting and installing or tape restore anyways, so the drive bay
    would save only a little time and a little risk of you botching the
    scsi id & termination jumpers.

    But even that is worthwhile if you support a lot of sites, especially if
    you have to send lesser techs out and talk them through the hard parts on
    the phone. The fewer variables the better. But aside from that, if the
    customer has BackupEdge or LoneTar or other good full crash recovery
    system, then even without hardware raid the hot swap bay is useful.
    The customer can buy a drive and pop it in and boot their backupedge
    recovery cd or floppy and do a full restore under their own power.
    At least they have the reasonable chance and choice to. There is nothing
    missing or preventing them. Most will never risk it, but I prefer to
    always be able to say that I make every effort to avoid committing the
    typical vendor/consultant lock-in tactics. I'll happily handle
    everything for the customer, but I always try not to stack the deck in
    my favor so they are forced to call me. Do unto others and all that.

    Also, once a particular scsi adapter/channel/id/lun address is
    configured into the kernel, it is _possible_ if you are super
    careful, to manually mount and unmount the device and maybe
    swap a drive in & out as a form of backup or massive data
    transport (like if tape is too slow or you need the random-access
    and dvd or rev drives aren't big enough etc...)
    I'd never recommend that simply because of the risk of
    electrical fluctuations corrupting or locking up the scsi bus,
    but I can _imagine_ situations where that would be the only
    way to meet some unlikely combination of needs and limitations
    of the customer. Even in that theoretical case I'd probably at
    the very least place such a drive bay on it's own seperate
    controller just as I do for tape drives.

    --
    Brian K. White brian@aljex.com http://www.myspace.com/KEYofR
    +++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
    filePro BBx Linux SCO FreeBSD #callahans Satriani Filk!


  7. Re: How to make a mirror disk

    On Oct 23, 12:20*am, "Brian K. White" wrote:
    > ----- Original Message -----
    > From: "JD"
    >
    > Newsgroups: comp.unix.sco.misc
    > To:
    > Sent: Wednesday, October 22, 2008 11:59 PM
    > Subject: Re: How to make a mirror disk
    >
    > > On Tue, 21 Oct 2008, Pat Welch wrote:

    >
    > >> JJ Jones wrote:

    >
    > >> Having a hot swap drive bay makes no sense unless you have hardware RAID.

    >
    > > Is this a SCO thing? This is certainly not true for Linux Software RAID..

    >
    > There is no software raid for sco.
    > (Actually, I think there might actually be some commercial
    > software lvm out there for open server, like vertas or maybe
    > something made by sco themselves, but I've never seen it or
    > used it myself. I'm not sure if it quite qualifies as a raid
    > implimentation, or if it supports hot adding/removing of
    > physical disks. But even so lets continue on the assumption
    > there is no software raid for open server.)
    >
    > The statement is mostly/usually, but still not quite true.
    > Hot swap bays would still drastically reduce the time and the chance of
    > scsi id/termination/etc jumper misconfig during drive replacement.
    >
    > It's true that normally, it's only via hardware raid and hot swap bays
    > that you can totally avoid an on-site visit to swap a drive. You can
    > often just mail a drive to the customer and someone there can pop it in.
    > Normally, on SCO, without hardware raid, there is not many times when
    > you would swap a drive and not need to be there yourself to do the
    > formatting and installing or tape restore anyways, so the drive bay
    > would save only a little time and a little risk of you botching the
    > scsi id & termination jumpers.
    >
    > But even that is worthwhile if you support a lot of sites, especially if
    > you have to send lesser techs out and talk them through the hard parts on
    > the phone. The fewer variables the better. But aside from that, if the
    > customer has BackupEdge or LoneTar or other good full crash recovery
    > system, then even without hardware raid the hot swap bay is useful.
    > The customer can buy a drive and pop it in and boot their backupedge
    > recovery cd or floppy and do a full restore under their own power.
    > At least they have the reasonable chance and choice to. There is nothing
    > missing or preventing them. Most will never risk it, but I prefer to
    > always be able to say that I make every effort to avoid committing the
    > typical vendor/consultant lock-in tactics. I'll happily handle
    > everything for the customer, but I always try not to stack the deck in
    > my favor so they are forced to call me. Do unto others and all that.
    >
    > Also, once a particular scsi adapter/channel/id/lun address is
    > configured into the kernel, it is _possible_ if you are super
    > careful, to manually mount and unmount the device and maybe
    > swap a drive in & out as a form of backup or massive data
    > transport (like if tape is too slow or you need the random-access
    > and dvd or rev drives aren't big enough etc...)
    > I'd never recommend that simply because of the risk of
    > electrical fluctuations corrupting or locking up the scsi bus,
    > but I can _imagine_ situations where that would be the only
    > way to meet some unlikely combination of needs and limitations
    > of the customer. Even in that theoretical case I'd probably at
    > the very least place such a drive bay on it's own seperate
    > controller just as I do for tape drives.
    >
    > --
    > Brian K. White * *br...@aljex.com * *http://www.myspace.com/KEYofR
    > +++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
    > filePro *BBx * *Linux *SCO *FreeBSD * *#callahans *Satriani *Filk!


    Brian,

    There is a software RAID for SCO called the Virtual Disk Manager.
    I've installed it for a couple of customers in the past, and a shiver
    runs down my spine every time I think of it. Stay as far away as
    possible. Hardware RAID is much, much easier, faster and more robust.

    Back to the original question from JJ Jones, the implication was that
    the IBM Netfinity in question has two drives installed, one in use and
    the other idle. I think this is unlikely unless the person who
    installed it was very inexperienced. I would encourage JJ to
    investigate exactly what hardware is installed. I am inclined to
    think these drives are already mirrored, which would be invisible to
    the casual observer, and he may only need to be able to access the
    controller firmware.

    If the system is not mirrored, someone would need to switch
    controllers on a live system. There are TAs to help do that on SCO's
    support website, but it's not for the faint of heart. There are also
    white papers on this issue on Microlite's and probably Lone-Tar's
    sites.

    JJ is probably wise to try to find somebody knowledgeable in his
    geographic area who can advise.

    Mark

  8. Re: How to make a mirror disk



    On Thu, 23 Oct 2008, Brian K. White wrote:

    >
    > ----- Original Message -----
    > From: "JD"
    > Newsgroups: comp.unix.sco.misc
    > To:
    > Sent: Wednesday, October 22, 2008 11:59 PM
    > Subject: Re: How to make a mirror disk
    >
    >
    >>
    >>
    >> On Tue, 21 Oct 2008, Pat Welch wrote:
    >>
    >>> JJ Jones wrote:
    >>>
    >>> Having a hot swap drive bay makes no sense unless you have hardware RAID.

    >>
    >> Is this a SCO thing? This is certainly not true for Linux Software RAID.

    >
    > There is no software raid for sco.
    > (Actually, I think there might actually be some commercial
    > software lvm out there for open server, like vertas or maybe
    > something made by sco themselves, but I've never seen it or
    > used it myself. I'm not sure if it quite qualifies as a raid
    > implimentation, or if it supports hot adding/removing of
    > physical disks. But even so lets continue on the assumption
    > there is no software raid for open server.)
    >
    > The statement is mostly/usually, but still not quite true.
    > Hot swap bays would still drastically reduce the time and the chance of
    > scsi id/termination/etc jumper misconfig during drive replacement.
    >
    > It's true that normally, it's only via hardware raid and hot swap bays
    > that you can totally avoid an on-site visit to swap a drive. You can
    > often just mail a drive to the customer and someone there can pop it in.
    > Normally, on SCO, without hardware raid, there is not many times when
    > you would swap a drive and not need to be there yourself to do the
    > formatting and installing or tape restore anyways, so the drive bay
    > would save only a little time and a little risk of you botching the
    > scsi id & termination jumpers.
    >
    > But even that is worthwhile if you support a lot of sites, especially if
    > you have to send lesser techs out and talk them through the hard parts on
    > the phone. The fewer variables the better. But aside from that, if the
    > customer has BackupEdge or LoneTar or other good full crash recovery
    > system, then even without hardware raid the hot swap bay is useful.
    > The customer can buy a drive and pop it in and boot their backupedge
    > recovery cd or floppy and do a full restore under their own power.
    > At least they have the reasonable chance and choice to. There is nothing
    > missing or preventing them. Most will never risk it, but I prefer to
    > always be able to say that I make every effort to avoid committing the
    > typical vendor/consultant lock-in tactics. I'll happily handle
    > everything for the customer, but I always try not to stack the deck in
    > my favor so they are forced to call me. Do unto others and all that.
    >
    > Also, once a particular scsi adapter/channel/id/lun address is
    > configured into the kernel, it is _possible_ if you are super
    > careful, to manually mount and unmount the device and maybe
    > swap a drive in & out as a form of backup or massive data
    > transport (like if tape is too slow or you need the random-access
    > and dvd or rev drives aren't big enough etc...)


    Under Linux, it is possible to mount a drive based on the UUID of the
    filesystem, so you don't need a consistent location in the /dev tree. It
    may take a little bit of fiddling to add a new partition to a running RAID
    system if the new partition is not at the same location in /dev as the old
    pertition, but it is possible.

    Using SCSI, one can rescan the bus on a live system. So it is quite useful
    to have hot-swap with software RAID.

    For backups to disk, one can use external enclosures (there are even some
    enclosures that allow a SATA drive to be dropped into it for a desktop
    hot-swap capability).


    > I'd never recommend that simply because of the risk of
    > electrical fluctuations corrupting or locking up the scsi bus,


    Basically, you don't trust the manufacturers of hot-swap drives and
    interfaces to design and manufacture working equipment?


  9. Re: How to make a mirror disk

    >> I'd never recommend that simply because of the risk of
    >> electrical fluctuations corrupting or locking up the scsi bus,

    >
    > Basically, you don't trust the manufacturers of hot-swap drives and
    > interfaces to design and manufacture working equipment?


    Naive.

    Rather, I trust my eyes when I have watched boxes lock up from
    hot inserting/removing perfectly good SCA2 drives in perfectly
    new high quality intel & other hot swap bays on lsi & adaptec
    hardware raid cards.

    In some cases it seemed to me like it maybe wasn't
    hardware/electrical fluctuations that caused the problem
    but weakness in the raid card firmware or in the os driver
    not handling the transitions as robustly as advertised.

    It doesn't matter what exactly was the cause of locking up
    the machine. It doesn't change the fact that it's stupid
    to poke it unnecessarily and regularly as if to dare it to crash.
    (outside of some testing and vetting situation where the goal is
    specifically to try as hard as possible to get something to fail)

    Just because it says on the box that something is ok to do,
    doesn't mean it is ok to risk customers livelihoods on
    such manufacturer claims of awsomeness.

    --
    Brian K. White brian@aljex.com http://www.myspace.com/KEYofR
    +++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
    filePro BBx Linux SCO FreeBSD #callahans Satriani Filk!


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