Re: RAID-5 design bug (or misfeature)

[Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>]

On Tue, 31 May 2005, Pavel Machek wrote:

> Hi!
>
> > > 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.
> >
> > I can't because mdadm is on that volume ... I solved it by booting from
> > floppy and editing raid superblocks with disk hexeditor but not every user
> > wants to do it; there should be at least kernel boot parameter for
> > it.
>
> Well, you should not use hexedit... just boot from rescue cd and run
> mdadd from it. No need to pollute kernel with that one.

Hi!

I think editing superblock with hexedit is less dangerous than using
raid-tools --- with editor I know what changes I have made and I can
revert them. With raid-tools, if you create wrong /etc/raidtab (original
was on failed volume too), it will trash superblocks completely.

I still think it's stupid that Linux modifies RAID superblocks into
irreversible state.

BTW. that server doesn't have CD drive. It was installed from network.

Mikulas

> 								Pavel
>
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