DISK CACHE CONTROL METHOD, DISK ARRAY DEVICE, AND STORAGE DEVICE

摘要

The LRU method which is currently used as a standard method for cache control is not able to provide efficient control in such an environment that a disk array is used, namely, a plurality of applications operate in a multiplexed state, because the method only uses access frequencies for the control. Therefore, a volume is divided into a plurality of areas having a plurality of arbitrary fixed lengths and access frequencies are acquired at every divided area and, at the time of assigning a disk cache, the disk cache is controlled so that the areas can be deprived in the order of access frequencies from the area having the lowest frequency. Consequently, the hit rate of disk caches can be improved by performing disk cache control in accordance with the access characteristic.