Computer system, storage system and method for saving storage area by integrating same data

A storage system coupled to a server, comprising:

• a disk drive for storing data;
• and
• a controller for controlling the disk drive, wherein:
• the controller manages a physical storage area of the disk drive for each of a plurality of physical blocks of predetermined sizes, and 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 controller
• stores data written in the first logical block in the first physical block allocated to the first logical block,
• refers to, upon reception of a request for copying data stored in the first logical block to the second logical block, a flag included in the request,
• further allocates the first physical block to the second logical block when the flag indicates permission of further allocation of the first physical block to the second logical block, 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 the flag indicates nonpermission of further allocation of the first physical block to the second logical block.

A method of controlling a computer system, the computer system comprising a server and a storage system,

• the server including an interface coupled to the storage system, a processor coupled to the interface, and a memory coupled to the processor,
• the storage system including a disk drive for storing data, and a controller for controlling the disk drive, managing a physical storage area of the disk drive for each of a plurality of physical blocks of predetermined sizes, and managing allocation of the plurality of physical blocks to a plurality of logical blocks of predetermined sizes,
• the plurality of physical blocks including at least one first physical block and at least one second physical block different from the first physical block,
• the plurality of logical blocks including at least one first logical block and one or more second logical blocks,
• the method comprising:
• storing data written in the first logical block in the first physical block allocated to the first logical block;
• referring to a flag included in a request when the storage system receives a request for copying data stored in the first logical block to the second logical block;
• further allocating the first physical block to the second logical block when the flag indicates permission of further allocation of the first physical block to the second logical block;
• and
• allocating the second physical block to the second logical block to store target data of the request for copying in the second physical block when the flag indicates nonpermission of further allocation of the first physical block to the second logical block.