Patent ID: 9176858
Filing Date: 2015-11-03
Classification: G06F

Abstract:
1. A storage system comprising: a plurality of first storage devices; and a first controller; wherein the first controller: provides a plurality of virtual volumes each composed of a plurality of virtual storage areas to a host computer coupled thereto; manages a real pool composed of a plurality of real storage areas; and when data transmitted from the host computer is received, the first controller: allocates a real storage area unallocated to the plurality of virtual storage areas out of the plurality of real storage areas as an uncompressed real storage area to a virtual storage area where the data has been transmitted out of the plurality of virtual storage areas; stores the data in the allocated real storage area; receives a user input to set a capacity depletion threshold that triggers an expansion of real pool capacity when exceeded and prompts the user when the capacity depletion threshold is exceeded; determines a data compression start threshold and a data compression end threshold based on the capacity depletion threshold such that the data compression start threshold is 10% less than the capacity depletion threshold and the data compression end threshold is 20% less than the capacity depletion threshold; if a real pool usage ratio, which is a rate of real storage areas allocated to the plurality of virtual storage areas out of the plurality of real storage areas constituting the real pool, exceeds the data compression start threshold, the first controller: executes compression processing of the virtual volumes based on an order of compression target priority set respectively to the plurality of virtual volumes; and stops execution of the compression processing if the real pool usage rate falls below the data compression end threshold.