Patent ID: 8230188

Claim:
A storage management apparatus that manages a storage device such that the storage device includes an opened area and a closed area, and that controls the storage device such that data is redundantly stored in each of the opened area and the closed area, the storage management apparatus comprising: an area laying-open unit that deletes or compresses data stored in at least two closed areas, converts one of the closed areas having stored the deleted data or the compressed data into the opened area, writes data corresponding to a write request to the converted opened area, and writes the data corresponding to the write request to at least one of the other closed areas having stored the deleted data or the compressed data, when the write request of the data has been made while a capacity stored in the storage device reaches a given value; and a re-redundancy unit that converts a part of or whole memory area of an add-on storage device into the closed area and copies data in an opened area placed in a redundant-storing relationship with the data deleted or compressed by the area laying-open unit, to the closed area, when the storage device is added on, wherein the closed area is a memory area capable of being accessed only by a user with given authority and the opened area is a memory area capable of being accessed by both the user with given authority and one or more other users without given authority.