From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Greaves Subject: Re: Problem with 5disk RAID5 array - two drives lost Date: Sat, 22 Apr 2006 20:54:05 +0100 Message-ID: <444A89DD.2000803@dgreaves.com> References: <62b0912f0604212054m40283fdbybdb6cd89e61dd153@mail.gmail.com> <17482.34615.908339.197028@fisica.ufpr.br> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17482.34615.908339.197028@fisica.ufpr.br> Sender: linux-raid-owner@vger.kernel.org To: Carlos Carvalho Cc: linux-raid@vger.kernel.org, tbostrom@writemem.com List-Id: linux-raid.ids Carlos Carvalho wrote: > Molle Bestefich (molle.bestefich@gmail.com) wrote on 22 April 2006 05:54: > >Tim Bostrom wrote: > >> raid5: Disk failure on hdf1, disabling device. > > > >MD doesn't like to find errors when it's rebuilding. > >It will kick that disk off the array, which will cause MD to return > >crap (instead of stopping the array and removing the device - I > >wonder), again causing 'mount' etc. to fail. > > > >Quite unfortunate for you, since you have absolutely no redundancy > >with 4/5 drives, and you really can't afford to have the 4th disk > >kicked just because there's a bad block on it. > > Yes... > > As Molle says, you have a chance that it's a driver/cable problem. > What you can also do is dd the disk to another one and try to rebuild > the array with the new disk so that you won't get errors during the > reconstruction. If you get errors during the copy you'll have to > decide what to do with the bad blocks. Some people prefer to use > ddrescue instead of dd; I've never tried it. I've used ddrescue and would *highly* recommend it. Use the GNU version, not the other one (dd_rescue?) It handles errors very well indeed and has a good display to show what's happening. It seems faster than dd (possibly threaded so streams both drives rather than read a drive, write a drive) David