Subject: Re: Bad sectors vs RAIDframe
To: Thor Lancelot Simon <>
From: Stephen Borrill <>
List: netbsd-users
Date: 06/07/2005 11:23:23
On Mon, 6 Jun 2005, Thor Lancelot Simon wrote:
> Luckily, this gives you an easy way to recover this drive: add it back to
> the set (as a spare if necessary) and tell RAIDframe to rebuild onto it, and
> away you go.  But with two bad drives in a parity RAID set you may have
> more work to do. :-/

I'm prepared for that. :-)

> We got a bad run of Samsung Spinpoint drives that we unfortunately
> installed in NetBSD Foundation servers about a year ago.  I have had
> to recover several of them (all in 2-way RAIDframe mirrors) by using
> dd to copy the data from the corresponding sectors on one drive over
> the bad sectors of the other, often doing this in both directions to
> recover from multi-drive failures within a set.

Yep, considered that, but I figured that if the components failed at 
different times, data may differ as the mirrors will have diverged.

> Since then, RAIDframe has been changed so that it retries on disk error 
> before failing a component, and never fails components from 
> non-redundant sets -- so a newer kernel may let you get somewhere with 
> data recovery, too.

How new is newer? They are currently running 1.6.2, but we can easily 
upgrade to 2.0. I guess we could temporily boot with -current just to do 
the recovery.