CMMVC9420E The storage pool cannot be deleted because it has an out of sync volume copy in a storage pool with volume protection active, this copy will be deleted and the volume has received I/O within the defined volume protection period.

Explanation

This error can occur when an attempt is made to delete a storage pool that contains at least one mirrored volume that has an unsynchronized copy in another pool where volume protection is enabled, and the protected volume received I/O operations within the defined volume protection time period.