System of controlling data rebalance and its method

A data rebalance control system comprising:

• a plurality of storage devices including one and more memories;
• and
• at least one processor coupled to the plurality of storage devices,
• wherein the at least one processor:
• (A) stores, in the plurality of storage devices, capacity information including information indicating a plurality of physical capacities corresponding to the plurality of storage devices which include at least one storage device having a compression function, coupled to one and more computers included in a computer system,
• (B) determines instruction contents for an entity having a rebalance function, based on the capacity information,
• the rebalance function of the entity being a function of rebalancing data so that distribution of a plurality of logical capacities recognized by the entity;
• corresponding to the plurality of storage devices, becomes a predetermined distribution,
• the instruction contents including a definition about logical capacity distribution;
• and
• (C) transmits, to the entity, a rebalance instruction that is an instruction to rebalance data according to the determined instruction contents,
• wherein the rebalance control function:
• determines whether or not at least one of the plurality of storage devices satisfies a condition, including at least a physical residual capacity of the at least one of the plurality of storage devices, for requiring rebalance;
• and
• performs (B) and (C) when a result of the determination is true and does not perform (B) and (C) when the result of the determination is false, and
• wherein the condition is different in each of two and more storage devices, of the plurality of storage devices, and
• wherein the entity for (B) is at least one entity of one and more entities storing data in the storage device associated with the condition having the result of the determination being true.