Abstract: A storage system and a copy control method enabling copying of data stored in a first volume connected with a higher-level device to a second volume. The system and method include controlling an update using a first management table for managing an update during a period from reception of a copy instruction from the higher-level device to reception of a predetermined command, and transferring update data of the first volume to the second volume based on the update situation in the first management table.

Abstract: Pre-update data is copied from a first storage device onto a second storage device in response to an update instruction to update data on the backup target volume on the first storage device. A copy status of each data on the backup target volume is managed with position information of the data mapped thereto. If bad data is present in the data on the backup target volume, the position information indicating the position of the bad data is searched. In accordance with the copy status managed with the position information mapped thereto, it is determined whether the pre-update data of the bad data is stored on the second storage device.

Abstract: A copy source device includes bit map acquisition and bit map merge functions. In accordance with bit-map management information in which a bit map indicating the presence of written data is rounded, the bit map acquisition and bit map merger acquires required bit map from a copy destination device, and merges the acquired bit map to a corresponding bit map of the copy source device. The copy destination device includes bit-map management information updater. The bit-map management information updater updates bit-map management information indicating a write operation when the write operation has been performed during a copy suspend mode. During a copy resume mode, the copy source device requests the copy destination device to transfer the bit-map management information, and in response, the copy destination device transfers the bit-map management information.

Abstract: The present invention provides a control method for a storage system comprising the first process for copying information stored by a first storage apparatus which is accessed by an upper echelon apparatus to a second storage apparatus, the second process for judging whether or not storage contents of the first and second storage apparatuses are identical when a fault occurs in the first storage apparatus, and the third process for controlling so that the upper echelon apparatus accesses the second storage apparatus in place of the first storage apparatus if the storage contents of the first and second storage apparatuses are identical.