Cluster Node Configured to Mount on Boot

Result: Unavailable storage; downtime 
 

The signature
The file system defined within a cluster mount resource is mounted automatically upon booting.

The impact
Potential data corruption after fail-over, switch-over or node restart.

Technical details
In this example, the passive node is configured to automatically mount “/d01” on boot. If the passive node is restarted, it will attempt to mount a file system which is already mounted on the currently active node. In this case, data might become corrupted since typically a SAN LUN should only be accessed by a single server at a time. Note that the opposite scenario is problematic as well.  If the file system is configured to be mounted automatically on boot on the active node, then the same risk will exist after a fail-over  or switch-over.

Can it happen to me?
This is a very common gap in HA environments becuase it is difficult to constantly sync the configuration of the server with the cluster configuration.  As a result, configuration mismatches, such as the one described above, are created which lead to data protection and availability vulnerabilities