摘要 |
In order to provide HSM that can effectively use the storage capacity of an upper Tier in an HSM system, a lower Tier of the HSM system detects a group of files having the same data content from a plurality of files stored in the lower Tier, and keeps at least one of the real data of the group of files having the same data content while deleting the rest of the data. The upper Tier receives the process result from the lower Tier. Then, in response to a read request from the host computer that specifies a file included in the group of files and transferred to the upper Tier from the lower Tier, the upper Tier identifies the at least one of the data that is kept and corresponding to the specified file, and responds to the host computer. |