SSDs Poll – RAID5 or RAID10?

Posted on September 12, 2012 by IsThatSo

Filed under: SAN Volume Controller, SONAS, Storwize V7000 |

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4 Responses

  1. Rob Jodoin, on September 18, 2012 at 1:30 am said:

    My customer would prefer to have a RAID 6 option. They currently use R6 for all storage so they see implementing SSD with R5 in a shared ext pool or MDG as lowering the overall reliability of the subsystem to the lowest common denominator (R5)

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  2. Jim, on September 18, 2012 at 11:48 am said:

    My main reason for using RAID6 for spinning disks is the length of time that RAID5 rebuilds take combined with the high mechanical stress that those drives are under during the rebuild. SSD RAID5 rebuilds complete very quickly and with no mechanical stress on the SSDs, so my current feeling is that we don’t really need to do RAID6 on those.

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    • evilensky, on September 26, 2012 at 1:08 am said:

      Is there any significant risk that a RAID setup in a write-heavy scenario will wear-level the RAID group in a similar way, and hence risk failing all drives with a similar service life?

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      • Jim, on September 26, 2012 at 11:06 am said:

        I don’t think so. I take comfort from the fact that DS8800 supports SSDs only in RAID5 (not in RAID6 or RAID10). They are different SSDs but the question is the same.

        If IBM had concerns about SSDs in RAID5 on V7000 it would have been pretty easy to lock that option out.

        So if you have a warranty or mtce agreement, and you have a hot spare, RAID5 should be fine in my opinion, and the rebuilds will be pretty quick.

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