Re: Postgresql data integrity during RAID10 drive rebuild

On Wed, 2006-11-29 at 10:56, Steve Poe wrote:
> I need some input from the Postgresql community.
>
> Our animal hospital runs Postgresql 7.4 on a 6-disc RAID10. The
> database logs are on a separate RAID1.
>
> We're using an LSI MegaRAID 320-2X controller. The controller reports
> one 146GB SCSI disc has failed in the RAID10 performance is in
> "DEGRADED" mode. The database seems to be running fine but slower.
>
> I've never had to replace a disc in an array with Postgresql running
> on it. LSI says I can replace the disc and do a rebuild while
> everything is running. I am of course concerned about data
> integrity/corruption.
>
> Has anyone had to rebuild one of their disc in an array of their
> database?

Yep, I've done it a few times. A few tips:

backup your database with pg_dump. confirm you can restore on a test
machine.

replace the drive during the lowest traffic period for your database.

The LSI cards are very stable. I've replaced drives under them back in
the Ultra-320 days with removable caddies. I would imagine that as long
as you have the proper drive caddies you're set. If the drives are not
in removable caddies, you'll need to power down to safely unplug them.