Relationship between number of HD and Rebuild Time ? - Storage

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Thread: Relationship between number of HD and Rebuild Time ?

  1. Relationship between number of HD and Rebuild Time ?

    We are using a Windows Storage Server with 4 SATA HD as RAID 5
    configuration. The size of each HD is 232GB.

    One of the HD breaks down and we have inserted the spare one. However, it
    takes ages to rebuild.

    I would like to know
    1) If the RAID 5 is consisted of 5 HD, will the rebuild take a shorter
    period of time. Is there any optimal number of HDs used ?
    2) We also guest the long time is due to the SATA HD. How much difference
    is between the rebuild time between SCSI and SATA drives. Is it possible to
    give me a rough figure ?

    Peter



  2. RE: Relationship between number of HD and Rebuild Time ?

    Hi Peter,
    It really depends on what type of RAID you have. If its MS SW RAID 5, I
    haven't used it in awhile, but my last experience with it, initial creation
    of the RAID 5 took 5 hours, using same size disks as yours, only I had a
    small chunk taken out for a system mirror. I don't recall the rebuild time on
    that - but I think it was less that 24 hours.

    If you are using a h/w RAID, then it totally depends on the RAID card
    vendor. The initialize and rebuild times I've seen for RAID 5 range from 90
    minutes to 24+hours. The one that takes 90 minutes is the same for either 4
    or 5(or 6) drives. I don't have alot of experience with different types of
    data loaded on the RAID when rebuilding, so my times my not be reliable for
    rebuilding heavily loaded RAIDs.

    How long did it take to rebuild? 24 hours or less is probably reasonble.
    Two weeks is not - something is really wrong.

    I've never seen a RAID with more disks take less time to RAID - so I don't
    think adding one more will shorten the time - but once again, that could
    really depend on the vendor.

    HTH,
    Pat

    "Peter" wrote:

    > We are using a Windows Storage Server with 4 SATA HD as RAID 5
    > configuration. The size of each HD is 232GB.
    >
    > One of the HD breaks down and we have inserted the spare one. However, it
    > takes ages to rebuild.
    >
    > I would like to know
    > 1) If the RAID 5 is consisted of 5 HD, will the rebuild take a shorter
    > period of time. Is there any optimal number of HDs used ?
    > 2) We also guest the long time is due to the SATA HD. How much difference
    > is between the rebuild time between SCSI and SATA drives. Is it possible to
    > give me a rough figure ?
    >
    > Peter
    >
    >
    >


  3. Re: Relationship between number of HD and Rebuild Time ?

    Dear Pat,

    Many thanks for your advice.
    Does it mean that the RAID Group in the Windows Storage Server is not a
    Hardware RAID ? How to distinguish a Hardware one with a Software one ?

    Peter

    "pheising" wrote in message
    news:5F172C62-8630-45EF-83AD-05FE60416A75@microsoft.com...
    > Hi Peter,
    > It really depends on what type of RAID you have. If its MS SW RAID 5, I
    > haven't used it in awhile, but my last experience with it, initial
    > creation
    > of the RAID 5 took 5 hours, using same size disks as yours, only I had a
    > small chunk taken out for a system mirror. I don't recall the rebuild time
    > on
    > that - but I think it was less that 24 hours.
    >
    > If you are using a h/w RAID, then it totally depends on the RAID card
    > vendor. The initialize and rebuild times I've seen for RAID 5 range from
    > 90
    > minutes to 24+hours. The one that takes 90 minutes is the same for either
    > 4
    > or 5(or 6) drives. I don't have alot of experience with different types of
    > data loaded on the RAID when rebuilding, so my times my not be reliable
    > for
    > rebuilding heavily loaded RAIDs.
    >
    > How long did it take to rebuild? 24 hours or less is probably reasonble.
    > Two weeks is not - something is really wrong.
    >
    > I've never seen a RAID with more disks take less time to RAID - so I don't
    > think adding one more will shorten the time - but once again, that could
    > really depend on the vendor.
    >
    > HTH,
    > Pat
    >
    > "Peter" wrote:
    >
    >> We are using a Windows Storage Server with 4 SATA HD as RAID 5
    >> configuration. The size of each HD is 232GB.
    >>
    >> One of the HD breaks down and we have inserted the spare one. However,
    >> it
    >> takes ages to rebuild.
    >>
    >> I would like to know
    >> 1) If the RAID 5 is consisted of 5 HD, will the rebuild take a shorter
    >> period of time. Is there any optimal number of HDs used ?
    >> 2) We also guest the long time is due to the SATA HD. How much
    >> difference
    >> is between the rebuild time between SCSI and SATA drives. Is it possible
    >> to
    >> give me a rough figure ?
    >>
    >> Peter
    >>
    >>
    >>




  4. Re: Relationship between number of HD and Rebuild Time ?

    Peter,
    Open Disk Manager in Computer Management and see what shows up. If you can
    see the separate RAID disks and they are listed as being in a RAID 5 - you
    have software RAID. If the RAID array just appears to Windows as a single
    large disk, then you have hardware RAID. If its hardware RAID, check in
    Device Manager, you should see some device under SCSI and RAID controllers
    that is your RAID card or motherboard RAID controller. Most hardware RAIDs
    have a GUI for management, but if not there should be at least a BIOS
    interface you can get into during the boot sequence.

    How did you access the RAID to rebuild it? If you did it thro disk manager
    - then you most likely have Windows software RAID. I don't know of any h/w
    RAID that can be seen and/or rebuilt thro Disk Manager.

    Pat



    "Peter" wrote:

    > Dear Pat,
    >
    > Many thanks for your advice.
    > Does it mean that the RAID Group in the Windows Storage Server is not a
    > Hardware RAID ? How to distinguish a Hardware one with a Software one ?
    >
    > Peter
    >
    > > rebuilding heavily loaded RAIDs.
    > >
    > > How long did it take to rebuild? 24 hours or less is probably reasonble.
    > > Two weeks is not - something is really wrong.
    > >
    > > I've never seen a RAID with more disks take less time to RAID - so I don't
    > > think adding one more will shorten the time - but once again, that could
    > > really depend on the vendor.
    > >
    > > HTH,
    > > Pat
    > >
    > > "Peter" wrote:
    > >
    > >> We are using a Windows Storage Server with 4 SATA HD as RAID 5
    > >> configuration. The size of each HD is 232GB.
    > >>
    > >> One of the HD breaks down and we have inserted the spare one. However,
    > >> it
    > >> takes ages to rebuild.
    > >>
    > >> I would like to know
    > >> 1) If the RAID 5 is consisted of 5 HD, will the rebuild take a shorter
    > >> period of time. Is there any optimal number of HDs used ?
    > >> 2) We also guest the long time is due to the SATA HD. How much
    > >> difference
    > >> is between the rebuild time between SCSI and SATA drives. Is it possible
    > >> to
    > >> give me a rough figure ?
    > >>
    > >> Peter
    > >>
    > >>
    > >>

    >
    >
    >


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