Step 1: Log into the DNS-321/323/343 and go to the Advanced (Tools tab for the DNS-323 and 321) tab click RAID on the left side of the screen.
Note: Auto-rebuild should not be selected or the manual rebuild option will not be available.
Step 2: Click Manually Rebuild Now and the drives will begin to synchronize.
Step 3: Click the Status tab and verify the Sync Time Remaining. Once the Sync Time Remaining is Completed the RAID is now in sync.
Note: If sync time turns returns to 0 minutes and has a message Sync Time Remaining: Degraded still. You can perform a Disk Diagnostic to determine which drive is failing. To do this go to the Maintenance tab and click the Disk Diagnostic tab on the left hand side. Next select your drive(s) you wish to test and click Start.
Note: You can configure e-mail alerts to alert you when rebuilding is complete or the status becomes degraded.