What is the difference between a disk pool and a storage unit in NetBackup?

A disk pool is a logical grouping of disk volumes, while a storage unit is a physical device that stores backup data.

A disk pool is a physical device that stores backup data, while a storage unit is a logical grouping of disk volumes.

A disk pool is a logical grouping of disk volumes, while a storage unit is a logical entity that references one or more disk pools.

A disk pool is a logical entity that references one or more storage units, while a storage unit is a logical grouping of disk volumes.