forcing a raid recovery

[Stephen Adler]

Hi all,

I'm putting together a backup system at my job and in doing so setup the 
good ol' raid 5 array. While I was putting the disk array together, I 
read that one could encounter a problem in which you replace a failed 
drive, the rebuilding processes will trip over another bad sector in on 
of the drives which was good before starting the rebuilding process and 
thus you end up with a screwed up raid array. So I was thinking of a way 
to avoid this problem. One solution is to kick off a job once a week or 
month in which you force the whole raid array to be read. I was thinking 
of possibly forcing a check sum of all the files I had stored on the 
disk. The other idea I had was to force one of the drives into a failed 
state and then add it back in and thus force the raid to rebuild. The 
rebuilding processes takes about 3 hours on my system which I could 
easily execute at 2am every Sunday morning.

Can anyone comment on this as a reliable way to exercise the disks in 
the array so that a bad sector doesn't get touched until a rebuild occurs?

thanks. Steve.