Dynamically mapped data storage subsystem having multiple open destage cylinders and method of managing that subsystem

摘要

A data storage subsystem dynamically maps a virtual data storage device image presented to associated processors to physical data storage devices used to implement the data storage subsystem. Multiple destage memory elements are concurrently active to increase an aggregate destage data transfer rate and to allow data to be stored on various memory elements appropriate to the type of data contained in each stored virtual object. An open logical cylinder list is used to maintain data integrity among multiple open destage memory elements. Memory elements are also selected to function as archive memory. The data storage subsystem includes a plurality of data storage elements configured into at least two redundancy groups, each redundancy group including n+m of the data storage elements, and a cache memory connected to the redundancy groups and a host processor interface. The data storage subsystem stores data indicative of the amount of available memory space on each of the open logical cylinders and little used data records are migrated or transferred from other memory elements to the archive memory elements to maintain sufficient available memory space.