In rare circumstances, a volume or snapshot may experience lost blocks. For example, if a power failure is followed by the failure of a control module cache battery (resulting from more than 72 hours of battery operation after the power failure or other factors), lost blocks may occur.
If volume blocks have been lost, the Volume Summary window (Figure 6: Volume Summary ) will display the current status of the volume as offline-lost-blocks. If snapshot blocks have been lost, the Volume Snapshots window (Figure 3: Volume Snapshots ) will display the current status of the snapshot as offline-lost-blocks.
In addition, an event message will be generated indicating the lost blocks.
To handle lost blocks, click the offline-lost-blocks link. The Acknowledge lost blocks dialog box appears (Figure 33: Acknowledge Lost Blocks ).
Figure 33: Acknowledge Lost Blocks
If lost blocks occur, you can do one of the following:
If an application attempts to read a lost block, an error will occur. If the block is rewritten, no error will occur, and the block will no longer be marked lost. The member or members containing volume or snapshot data will continue to show a status of RAID lost blocks until the blocks have been written with new data.
To retain the lost blocks, select Set the volume online but retain the lost blocks. The current status will be changed to online-lost-blocks.
This option may present a security risk, and the blocks may contain old data. The status will be cleared for the member or members containing volume or snapshot data.
To mark the lost blocks valid, select Mark the lost blocks valid and set the volume online. The current status will be changed to online.