Re: Fwd: hard drive failure under RAID-1
A question a bit apart, what has happened to RAID autodetect in the 2.4.x
On Tue, 25 Sep 2001, Russell Coker wrote:
> The following is something to consider when setting up RAID arrays. At the
> moment AFAIK every RAID solution suffers from this problem. :(
> I have a Linux software RAID-1 array consisting of two IBM IDE hard drives.
> The latest kernel works the same way as the 2.4.2 kernel I am using on that
> I have just had them both fail at the same time! They both had quite a
> number of bad sectors, however there was no sector that was bad on both
> The result I would have liked to see would be that when a bad sector is
> encountered during a read from disk 0, then disk 1 should then be read. If
> the data can be read from disk 1 then it should be written back to disk 0.
> If after that disk 0 can be read (the likely result using sector-sparing in
> hardware) then it should give lots of huge kprintf() errors and keep running.
> The result I saw was that disk 0 was marked as failed, then when a different
> sector failed on disk 1 the ext2 file system saw errors, the system stopped
> functioning correctly and needed a hard reset. Then it paniced on boot
> because it couldn't add either disk to the RAID-1. Since then I have been
> trying to recover it. I wrote a program to read both disks and take data
> from disk 1, but take it from disk 0 when disk 1 returned a bad sector. But
> this didn't work well because disk 1 had run for some time without disk 0.
> In summary a situation which could have been salvaged by an emergency visit
> to a computer store turned into a catastrophy. :(
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