CMMVC9411E The volume caching IO group cannot be removed from the volume access IO group set.

Explanation
This error can occur when an attempt is made to remove the volume caching I/O group from the
volume access I/O group set. The volume access I/O group set must include the volume caching I/O
group.

User response
Retry the command, specifying an I/O group that is not the volume caching I/O group. Alternately,
change the volume caching I/O group and then retry the command.