RAID5 SATA rebuild times - Storage

This is a discussion on RAID5 SATA rebuild times - Storage ; Hi, does anyone have any practical experience with rebuild times of SATA arrays? I've heard many recommendations suggesting that RAID5 SATA arrays with big (750GB, 1TB) disks should not have too many spindles due to long rebuild times - but ...

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Thread: RAID5 SATA rebuild times

  1. RAID5 SATA rebuild times

    Hi, does anyone have any practical experience with rebuild times of
    SATA arrays? I've heard many recommendations suggesting that RAID5
    SATA arrays with big (750GB, 1TB) disks should not have too many
    spindles due to long rebuild times - but how many spindles is 'too
    many'?

    I currently work on the basis of anything between 4+1 to 7+1 and it
    would be nice to have some evidence to support this. RAID6 would help
    but that's not an option unfortunately.

    Thanks
    Jono

  2. Re: RAID5 SATA rebuild times

    On Feb 7, 2:30 pm, Jono968 wrote:
    > Hi, does anyone have any practical experience with rebuild times of
    > SATA arrays? I've heard many recommendations suggesting that RAID5
    > SATA arrays with big (750GB, 1TB) disks should not have too many
    > spindles due to long rebuild times - but how many spindles is 'too
    > many'?


    I just finished a test early this morning on a Nexsan SATABoy
    containing a 13-member RAID-6 set consisting of 750GB drives (with 1
    hot spare in the 14-drive enclosure). We yanked a drive out and
    watched the rebuild - it took 18.5 hours. There wasn't much load on
    the array during this time and the rebuild priority was set to
    "medium" - 3 on a scale of 1 to 5.

    How many spindles is "too many" depends on how you define "long
    rebuild times" and what level of risk you want to have while the
    raidset is rebuilding. Personally, I think that 18.5 hours is pretty
    darn good for a 7.5TB raidset.

    I did not do a test of a rebuild on a RAID5 set on this array.

    .../Ed




  3. Re: RAID5 SATA rebuild times

    Jono968 wrote:
    > Hi, does anyone have any practical experience with rebuild times of
    > SATA arrays? I've heard many recommendations suggesting that RAID5
    > SATA arrays with big (750GB, 1TB) disks should not have too many
    > spindles due to long rebuild times - but how many spindles is 'too
    > many'?
    >
    > I currently work on the basis of anything between 4+1 to 7+1 and it
    > would be nice to have some evidence to support this. RAID6 would help
    > but that's not an option unfortunately.


    The rebuild time of a SATA or SCSI or FC RAID5 array is as dependent on
    the raid controller as it is on number of spindles in the array and the
    trade-off between performance hit during the rebuild and the desire to
    restore redundancy.

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