Date: Thu, 27 Jan 2005 07:48:39 +0100
From: <pcg@goof.com ( Marc) (A.) (Lehmann )>
To: Andi Kleen <ak@muc.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: critical bugs in md raid5
Message-ID: <20050127064839.GA32165@schmorp.de>
Mail-Followup-To: Andi Kleen <ak@muc.de>, linux-kernel@vger.kernel.org
References: <20050127035906.GA7025@schmorp.de> <m1vf9j4fsp.fsf@muc.de>
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On Thu, Jan 27, 2005 at 06:11:34AM +0100, Andi Kleen <ak@muc.de> wrote:
> Marc Lehmann <linux-kernel@plan9.de> writes:
> >
> > The summary seems to be that the linux raid driver only protects your data
> > as long as all disks are fine and the machine never crashes.
> 
> "as long as the machine never crashes". That's correct. If you think

Thanks for your thoughts, btw :)

I forgot to mention that even if data is known to be lost it's much better
to return, say, EIO to higher levels than to completely shut down the
device (after all, this is no differnce to what other block devices behave).

Also, it's still likely that some old error can be repaired, as the broken
non-parity block might be old. This is probably better to be handled in
userspace, though, with special tools. But for them it might be vital to
get the correct disk index, to be able to detect the stripe layout.

It's usually much faster to repair and verify, as opposed to format and
restore, of course.

-- 
                The choice of a
      -----==-     _GNU_
      ----==-- _       generation     Marc Lehmann
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      --==---/ / _ \/ // /\ \/ /      http://schmorp.de/
      -=====/_/_//_/\_,_/ /_/\_\      XX11-RIPE
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