| 摘要 |
<p>A system according to this invention converts a full-copy snapshot into a differential snapshot. The system is composed of a storage subsystem (120) and a server subsystem (110). The storage subsystem comprises a disk drive and a disk controller (125). The server subsystem comprises an interface (14), a processor (11), and a memory (12). The disk controller provides storage areas of the disk drive as logical volumes, and stores a differential block bitmap (122). The processor (11) obtains the differential block bitmap, and identifies a block from the differential block bitmap. The processor obtains, from a full-copy snapshot volume (151), differential data that is stored in the identified block. The processor stores the obtained differential data in a differential volume (142). The processor stores, in differential block arrangement information, the location of the differential data stored in the differential volume.</p> |
