Re: Bad Blocks in IDE software Raid 1
On Thu, 17 Apr 2003 18:48, I. Forbes wrote:
> Am I correct in assuming that every time a "bad block" is discovered
> and remapped on a software raid1 system:
>
> - there is some data loss
I believe that if drive-0 in the array returns a read error then the data is
read from drive-1 and there is no data loss. Of course if the drive returns
bad data and claims it to be good data then you are stuffed.
> - one of the drives is failed out of the array
Yes.
> I assume there are repeated attempts at reading the bad block, before
> the above actions are triggerd.
Yes, this unfortunately causes things to block for a while...
> Hopefully these will trigger remapping
> at the firmware level before the above happens.
My experience is that IBM drives don't do this. It could be done but would
require more advanced drive firmware.
> Do you think there would be any benefit gained from "burning in" a
> new drive, perhaps by running "fsck -c -c", in order to find marginal
> blocks and get them mapped out before the drive is put onto an array?
Maybe.
> What about doing this on a aray drive that has "failed" before
> attempting to remount it with "raidhotadd".
Generally such a "burn-in" won't achieve any more benefit than just doing a
new raidhotadd. Although it has worked once for me and is something to keep
in mind.
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