Patent ID: 8135983

Claim:
A mirroring system connectable to a host computer and connectable to a plurality of hard disks, the mirroring system comprising: a rebuild unit configured to rebuild data stored in one hard disk of the plurality of hard disks to another hard disk of the plurality of hard disks; and a control unit configured, when a rebuilding process by the rebuild unit is interrupted when the mirroring system is started, to cause the rebuild unit to resume the rebuilding process, wherein the control unit is configured to cause the rebuild unit to resume the rebuilding process when a predetermined amount of time passes after the mirroring system is started, in a case where the mirroring system is started by a first resuming factor, and wherein the control unit is configured to cause the rebuild unit to resume the rebuilding process before the predetermined amount of time passes after the mirroring system is started, when the mirroring system is started by a second resuming factor.