Date: Sat, 18 Dec 2004 22:17:47 +0100 From: Bernd Walter <ticso@cicely12.cicely.de> To: Peter Jeremy <PeterJeremy@optushome.com.au> Cc: ticso@cicely.de Subject: Re: Multiple hard disk failures - coincidence ? Message-ID: <20041218211747.GE1068@cicely12.cicely.de> In-Reply-To: <20041218210720.GE97121@cirb503493.alcatel.com.au> References: <41C3D62D.7000808@comcast.net> <20041218091739.GC97121@cirb503493.alcatel.com.au> <20041218195910.GD1068@cicely12.cicely.de> <20041218210720.GE97121@cirb503493.alcatel.com.au>
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On Sun, Dec 19, 2004 at 08:07:20AM +1100, Peter Jeremy wrote: > On Sat, 2004-Dec-18 20:59:11 +0100, Bernd Walter wrote: > >On Sat, Dec 18, 2004 at 08:17:39PM +1100, Peter Jeremy wrote: > >> My approach to this is to add a line similar to > >> dd if=/dev/ad0 of=/dev/null bs=32k > >> for each disk into /etc/daily.local (or /etc/weekly.local or whatever). > >> This ensures that the disks are readable on a regular basis. > > > >Regular reading of every file is part of what I call backup. > > That only verifies the used part of the disk. Reading the unused parts That's true - used parts are the only I'm interested in reading. If blocks fail that aren't used write reallocation has to do it's job. > of the disk as well helps reduce surprises. Also, in a mirrored environment, > the backup does not ensure that the data can be read off both disks. > (Or the parity area for RAID-5). Raid is another story. Just dd'ing the disks wouldn't check redundance integrity, but if you check the integrity why would you still want to check via dd too? -- B.Walter BWCT http://www.bwct.de bernd@bwct.de info@bwct.de
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