When a high priority operation attempted to find an available drive, all the drives were in use. To make a drive available for this operation, the indicated process is being cancelled by the system.
The lower priority process is cancelled to make a mount point (drive) available.
When a drive again becomes available, restart the process that was cancelled. If the process was a migration or reclamation process, it will be automatically restarted when needed. If this message appears frequently, you may want to increase the number of drives available. See the MOUNTLIMIT parameter on the UPDATE DEVCLASS command.