A processor, operable in a computing storage environment, for each rank in a storage management device in the computing storage environment, allocates a lower maximum count defined by a predetermined lower maximum count of Task Control Blocks (TCBs) of a rank for performing destage operations, and a higher maximum count of TCBs to be implemented for performing a storage operation, and performs the storage operation using up to the lower maximum count of TCBs, yet only allows those TCBs above the lower maximum count to be allocated for performing the storage operation satisfying at least one criterion.