provided are a method , system , and program for managing storage units . storage pool information indicates an assignment of a plurality of storage units to a plurality of storage pools , wherein each pool is assigned zero or more storage units , and wherein data associated with one storage pool is stored in at least one storage unit assigned to the storage pool . user selection is received to move at least one storage unit to a target storage pool . a determination is made of at least one storage unit assigned to a source storage pool to move to the target storage pool . the storage pool information is updated to indicate the determined at least one selected storage unit as assigned to the target storage pool .