In a digital data storage system, cache storage space is used to accelerate sponsor access to a data document. Adaptive throttling is used to control the storage area subsystem, permitting the storage manager to delay treatments.

The electronic data storage system comprises a storage manager 35, a décadence directory twenty-two and a plurality of storage quantities 62. Foc storage twenty is used to maintain premigrated files. When a fresh data document is expected by the coordinate processor, it is copied towards the selected storage volume. During the migration of any data document to the chosen storage quantity, a “cache hit” occurs.

A storage supervisor controls the 1st premigration of data files and the subsequent migration. It also maintains reference info for the premigrated data. These include the logical quantity identifier (LVI) 44, a pointer to the data record and a storage volume level counteract 46, which is the position inside sequential media.

Hosting server processing systems, such as a mainframe or a personal computer, generate info and request a logical volume from the virtual info storage system. The data file is copied from casemate storage 20 to the storage area volume. The migrated files happen to be then recalled from the storage subsystem.

To shield the capacity for the cache storage area, the storage space manager runs the following output and input operations. First of all, the storage manager keeps track of the amount of free of charge space. Whether it drops down below a threshold, it computes a accelerator. This is an adjustment of performance that is certainly more significant over a cache space threshold.