Re: software RAID

Valdis.Kletnieks_at_vt.edu
Date: 05/20/05

  • Next message: Bjorn Helgaas: "Re: [patch 1/1] Proposed: Let's not waste precious IRQs..." 
    To: lsorense@csclub.uwaterloo.ca (Lennart Sorensen)
Date:	Fri, 20 May 2005 16:21:11 -0400

    On Fri, 20 May 2005 16:03:34 EDT, Lennart Sorensen said:

    > If you have a bad sector, it doesn't go away by writing to it again. On
    > modern drives, if you see bad sectors the disk is just about dead, and
    > will probably be seen as such by the raid system which will then stop
    > using the disk entirely and expect you to replace it ASAP.

    The one exception here is if you have a miswritten sector (usually caused by
    unexpected power-down), which won't read back correctly - but running badblocks
    with one of the 'write-verify' options will resurrect it.

    If you have a drive that has a bad block in it even *after* badblocks has
    re-written it, it's time to replace the drive *now*....

    For the original poster: Breaking the mirror and then re-mirroring from the
    "good" drive *might* recover the bad block when it re-writes it. But don't bet
    on it...

    ("power fail" is about the only cause of recoverable bad blocks that I know of -
    and if you're having power-fail issues on a RAID, I'd recommend you fix
    *THAT* problem before it causes you more grief. A good UPS will more than pay
    for itself in sysadmin sanity and peace of mind....)

    -
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  • Next message: Bjorn Helgaas: "Re: [patch 1/1] Proposed: Let's not waste precious IRQs..."

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