Storage switch, storage system, and data copying method

A storage system for copying data in accordance with a bitmap, the storage system comprising:

• a storage device for storing data;
• a first bitmap generator for generating a first bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of regions each having a predetermined partition size and being associated with each of the index bits of the first bitmap;
• a controller for controlling copying of data in a part of the regions to another part of the regions;
• a first modifier for modifying at least one of the index bits associated with at least one of the regions having undergone a copying;
• a second bitmap generator for generating a second bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of sub-regions each having a partition size smaller than the predetermined partition size and being associated with each of the index bits of the second bitmap, the controller controlling writing of data into at least one of the sub-regions addressed by a write request from the exterior;
• a second modifier for modifying at least one of the index bits corresponding to the at least one sub-regions addressed by the write request from the exterior;
• and
• a merging controller for controlling to generate a third bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of sub-regions each having the same size as the partition size, the merging controller, when the writing of data is performed during the copying of data, modifying a part of the index bits in the third bitmap corresponding to a part of the index bits of the first bitmap modified by the first modifier on account of the copying of data performed before the writing of data, and merging the second bitmap modified by the second modifier and the third bitmap modified by the merging controller;
• the controller resuming copying of data of any sub-regions on the basis of the merged bitmap.

A data copying method of copying data in accordance with a bitmap, comprising:

• generating a first bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of regions each having a predetermined partition size and being associated with each of the index bits of the first bitmap;
• controlling copying of data in a part of the regions to another part of the regions;
• modifying, regarding to the first bitmap, at least one of the index bits associated with at least one of the regions having undergone a copying;
• generating a second bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of sub-regions each having a partition size smaller than the predetermined partition size and being associated with each of the index bits of the second bitmap;
• controlling writing of data into at least one of the sub-regions addressed by a write request from the exterior;
• modifying, regarding to the second bitmap, at least one of the index bits corresponding to the at least one sub-regions addressed by the write request from the exterior;
• controlling to generate a third bitmap including a plurality of index bits which render the storage area to be partitioned into a plurality of sub-regions each having the same size as the partition size;
• when the writing of data is performed during the copying of data, modifying a part of the index bits in the third bitmap corresponding to a part of the index bits of the modified first bitmap on account of the copying of data performed before the writing of data;
• merging the modified second bitmap and the modified third bitmap;
• and
• resuming copying of data of any sub-regions on the basis of the merged bitmap.