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Date: Sun, 19 Dec 2004 08:07:20 +1100
From: Peter Jeremy <PeterJeremy@optushome.com.au>
To: ticso@cicely.de
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cc: freebsd-hackers@freebsd.org
cc: Gary Corcoran <garycor@comcast.net>
Subject: Re: Multiple hard disk failures - coincidence ?
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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
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).

-- 
Peter Jeremy