forcing a raid recovery

[Tom Metro]

Stephen Adler wrote:
> One solution is to kick off a job once a week or 
> month in which you force the whole raid array to be read.

If you are using Linux software RAID, on Ubuntu (and probably Debian) 
the default setup for mdadm includes a cron job that runs checkaray 
monthly on the first Sunday of the month. (The checkaray script sends 
the same command to the md driver as what is described at the "Data 
Scrubbing" link Bill Bogstad posted.)


> 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?

As Bill Bogstad mentioned, the above won't exercise the entire disk, 
which is why I'd recommend running smartd, and configuring it to run a 
long test weekly, which supposedly will perform a read scan of the 
entire drive. A SMART failure won't trigger a RAID failure, but if you 
setup alerts from smartd, you can manually fail the bad drive and 
replace it.

  -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/