Patent ID: 9459973
Filing Date: 2016-10-04
CPC Classification: G06F

Claim Text:
1. A storage subsystem coupled to a host computer, comprising: a plurality of storage devices for storing data sent from the host computer; a processor for managing a storage area of the storage devices; and a memory for storing management information of the storage area, wherein the processor is programmed to: perform tiering of the plurality of storage devices; manage each tier subjected to tiering by providing a priority order based on a performance or a property of each of the plurality of storage devices; manage an access frequency which is a number of accesses per unit time of data in the plurality of storage devices per tier; extracts data being a candidate of migration by referring to the access frequency per tier, and migrate the data to a higher tier having a higher priority or to a lower tier having a lower priority than the tier in which said data is stored; calculate an increment capacity of write data being written to the tier within a predetermined period of time per tier; and execute a verification processing of detecting and restoring a defect of a storage media of the plurality of storage devices regarding the storage area of each tier corresponding to the calculated data increment capacity before using said storage area, wherein the increment capacity of write data is either any one of the following, or a total of two or more of the following: (d1) a capacity of data written via migration from the higher tier; (d2) a capacity of data written via migration from the lower tier; or (d3) a capacity of data written from the host computer, wherein each of the capacity of data of (d1) through (d3) is calculated so that a total value of a predetermined period of time determined in advance based on an actual value per predetermined time unit becomes maximum, and wherein the predetermined unit time is any one of the following units: per minute, per hour, per day, per week, or per month.