7.3 Recovering a Mirror where All Elements Report ‘Not in Sync’

If all elements of a mirrored RAID report a status of “not in sync”, use the following procedure to recover the mirror.

  1. Determine which element you believe to be the in-sync element.

  2. Log in to the server as the root user, then open a terminal console.

  3. Using the nlvm delete raid segment command, remove all of the elements from the mirror except the element you want to keep.

    For each element that you want to remove, enter the following command. When you are prompted to confirm, type yes, then press Enter. Wait for the segment to be removed before you remove the next segment.

    nlvm --force delete raid <raid_name> segment <segment_number>

    Use the --force NLVM option to force the deletion of an out-of-sync segment. When you are done, you have a RAID1 device that consists of the single element that you believed to be the in-sync element.

    For example, enter

     nlvm -f delete raid MYRAID1 segment 0

    When prompted to confirm the deletion, type yes, then press Enter.

  4. Force the single RAID element to be in sync. At the command prompt, enter

    nlvm raid force <raid_name>
  5. Add elements back into the mirror as desired by using the nlvm raid expand command. At the command prompt, enter

    nlvm expand raid <raid_name> device=<device_name>

    The device option can be specified multiple times to specify additional segments.