Patent ID: 7631218
Filing Date: 2009-12-08
Classification: G06F

Abstract:
1. A RAID system for accessing a connected disk device according to an I/O request requested from a host and executing the I/O request, comprising: a plurality of the disk devices constituting the RAID; and a controller for executing Rebuild or Copy back processing for reconstructing a RAID configuration, when one of the plurality of disk devices fails, by executing in parts a plurality of times of operation to read data of a disk device, other than the failed disk device, and to write data to a spare disk device or a new disk device, wherein the controller judges whether a normal I/O request, including an I/O request from the host, does not arrive for a predetermined time, and when a normal I/O request does not arrive for a predetermined time, sets larger the request processing size for one time of Rebuild or Copy back processing, which is to be executed in parts for a plurality of times, compared with the size in the case when the normal I/O request arrives within the predetermined time, wherein the controller executes balancing the normal I/O request and a request for one time of the Rebuild/Copy back, and issues the next Rebuild/Copy back request according to the completion of processing of the Rebuild/Copy back request; wherein when a normal I/O request does not arrive for a predetermined time, the controller sets the request processing size for one time of the Rebuild or Copy back processing to be a multiple of the processing size of the case when the I/O request arrives within the predetermined time.