Patent ID: 7958328

Claim:
A computer system, comprising: a server; and a storage system, wherein: the server includes: an interface coupled to the storage system; a processor coupled to the interface; and a memory coupled to the processor; the storage system includes: a disk drive for storing data; and a controller for controlling the disk drive; the storage system manages a physical storage area of the disk drive for each of a plurality of physical blocks of predetermined sizes; the storage system manages allocation of the plurality of physical blocks to a plurality of logical blocks of predetermined sizes; the plurality of physical blocks include at least one first physical block and at least one second physical block different from the first physical block; the plurality of logical blocks include at least one first logical block and one or more second logical blocks; and the storage system stores data written in the first logical block in the first physical block allocated to the first logical block, judges, upon reception of a request for copying data stored in the first logical block to the second logical block, whether further allocation of the first physical block to the second logical block is permitted or not based on information included in the request for copying data, further allocates the first physical block to the second logical block when it is judged that further allocation of the first physical block to the second logical block is permitted based on the information, and allocates the second physical block to the second logical block to store target data of the request for copying in the second physical block when it is judged that further allocation of the first physical block to the second logical block is not permitted based on the information.