If a node or an I/O group fails, you can use the command-line interface (CLI) to recover offline volumes.
If you have lost both nodes in an I/O group and have, therefore, lost access to all the volumes that are associated with the I/O group, you must complete one of the following procedures to regain access to your volumes. Depending on the failure type, you might have lost data that was cached for these volumes and the volumes are now offline.
Data loss scenario 1
One node in an I/O group has failed and failover has started on the second node. During the failover process, the second node in the I/O group fails before the data in the write cache is flushed to the backend. The first node is successfully repaired but its hardened data is not the most recent version that is committed to the data store; therefore, it cannot be used. The second node is repaired or replaced and has lost its hardened data, therefore, the node has no way of recognizing that it is part of the system.
Complete the following steps to recover an offline volume when one node has down-level hardened data and the other node has lost hardened data:
Data loss scenario 2
Both nodes in the I/O group have failed and have been repaired. The nodes have lost their hardened data, therefore, the nodes have no way of recognizing that they are part of the system.
Complete the following steps to recover an offline volume when both nodes have lost their hardened data and cannot be recognized by the system: