Sometimes a drive fails, or a RAID controller goes down on an array with a redundant drive (eg – RAID 5 or RAID 3) and the parity on a RAID must be rebuilt. This should happen as quickly as possible. However, it can result in data loss and in the event of a second drive failure on the array most of the data could be lost. The data may be safe, and should be backed up as quickly as possible. Once the data is backed up, then you should perform a rebuild of the parity for the array.
To do so open RAID Admin from /Applications/Server and click on the RAID containing the damagemed array and click on the Advanced button in the toolbar. Then enter the management password for the Xserve RAID you are rebuilding the parity for. Next, click on the button to Verify or Rebuild Parity and click on Continue, selecting the array. Now click Rebuild Array and wait a few hours during the rebuild process. Once the rebuild is complete, perform a Verify Array on the RAID. Finally, verify the data on the volumes.
If the rebuild of the data does not go well and the array is lost then you will likely need to delete the array and readd it. In many cases, this will cause you to loose the data that was stored on that array and therefore the data on the volume, one of the many good reasons for backup.
