On a basic server setup you might have a mirrored volume, and it might go "out of sync" or have other issues, data on mirrored drives can become out of sync.
Here are a few tips to repair/fix it:
- If the status is Missing or Offline, be sure that the drive has power and is connected properly. Then start Disk Management, right-click the failed volume, and click Reactivate Volume. The drive status should change to Regenerating and then to Healthy. If the volume doesn’t return to the Healthy status, right click the volume, and then click Resynchronize Mirror.
- If the status is Online (Errors), right-click the failed volume, and then click Reactivate Volume. The drive status should change to Regenerating and then to Healthy. If the volume doesn’t return to the Healthy status, right-click the volume, and then click Resynchronize Mirror.
- If one of the drives shows a status of Unreadable, you might need to rescan the drives on the system by choosing Rescan Disks from Disk Management’s Action menu. If the drive status doesn’t change, you might need to reboot the computer.
- If one of the drives still won’t come back online, right-click the failed volume, and then click Remove Mirror. Next, right-click the remaining volume in the original mirror, and then click Add Mirror. You now need to mirror the volume on an unallocated area of free space. If you don’t have free space, you need to create space by deleting other volumes or replacing the failed drive.
