Re: RAID-5 design bug (or misfeature)

From: Stephen Frost
Date: Mon May 30 2005 - 08:24:52 EST


* Alan Cox (alan@xxxxxxxxxxxxxxxxxxx) wrote:
> On Llu, 2005-05-30 at 03:47, Mikulas Patocka wrote:
> > > In article <Pine.LNX.4.58.0505300043540.5305@xxxxxxxxxxxxxxxxxxxxxxxx> you wrote:
> > > > I think Linux should stop accessing all disks in RAID-5 array if two disks
> > > > fail and not write "this array is dead" in superblocks on remaining disks,
> > > > efficiently destroying the whole array.
>
> It discovered the disks had failed because they had outstanding I/O that
> failed to complete and errorred. At that point your stripes *are*
> inconsistent. If it didn't mark them as failed then you wouldn't know it
> was corrupted after a power restore. You can then clean it fsck it,
> restore it, use mdadm as appropriate to restore the volume and check it.

Could that I/O be backed out when it's discovered that there's too many
dead disks for the array to be kept online anymore?

Just a thought,

Stephen

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