2 degraded disk in raid 5

[Jason Edgecombe]

Bruce wrote:
> I need some guidance on what the next steps to take on this problem.  The
> problem is on a poweredge 2550 that has a 2 disk raid 1 for the OS and a 3
> disk raid 5.  Two of the 3 disk raid 5 have degraded in the last 8 hours.
> What steps do I need to take in order to save the 3 disk raid 5?  I have
> never had to deal with this before. 
>   
Here is what to do:

Check the manual for you model of Dell and RAID.

Use the following instructions AT YOUR OWN RISK!

Step 1. Is the data on the RAID5 set still readable?
If not, the data on the degraded RAID 5 is hosed, so replace the 
degraded disks, restore from backup, and you're finished.
If yes, proceed to step 2.
Step 2. Shutdown all services and make sure the system is in a idle 
state with no one writing to disk. switching to single-user mode should 
do it. (i.e. "telinit 1")
Step 3. Make a backup of all data on the RAID 5 set. Include the data on 
the RAID1 set for extra peace of mind.
Step 4. Verify the backup against the live data.
Step 5. Using the indicator lights or the Dell RAID software or the Dell 
RAID BIOS, determine which drive has failed.
Step 6. Replace the failed drive. Replace ONLY ONE DRIVE! If you have 
quick-remove trays, then I think you can pull the drive out on the live 
system. If you believe the drive is still good, then remove the drive 
and re-insert it.
Step 7. Wait for the RAID set to rebuild. Use the RAID BIOS or Dell RAID 
tools to check the progress and status.
Step 8. Make sure the drive is no longer degraded or failed. If it's 
still degraded or failed, replace the drive if you just reinserted it 
and go back to step 7.
Step 9. Go back to step 5 and loop until the RAID set is healthy. If you 
replace both disks with no improvement, then call Dell.

Jason