Abstract: Provided is a storage apparatus to provide a data storage area to an external apparatus. The storage apparatus includes a storage drive to provide a physical storage area for the data storage area; and a storage control unit to manage the data storage area as an un-compression storage area that is a logical storage area for storing data in the external apparatus in an uncompressed form and as a compression storage area that is a logical storage area for storing data in the external apparatus in a compressed form, and to control each of data write processing and data read processing on the storage drive according to a data input-output request from the external apparatus. The compression storage area and the un-compression storage area each include a set of unit physical storage areas formed by dividing the physical storage area.

Abstract: A storage apparatus obtains a snapshot(s) of a first logical volume when needed and saves old data to a second logical volume when data is written to the first logical volume after obtaining the snapshot. A storage area of the second logical volume is allocated in chunk units to the first logical volume and a tendency of order to delete snapshots is judged when the chunks have been completely used up. If there is a tendency to delete the snapshots in their acquisition order, a new chunk is allocated to the first logical volume and a storage area in that chunk is determined to be a save location of the old data. If there is a tendency to delete the snapshots randomly, an unused storage area in a chunk already allocated to the first logical volume is determined to be the save location of the old data.

Abstract: A storage apparatus obtains a snapshot(s) of a first logical volume when needed and saves old data to a second logical volume when data is written to the first logical volume after obtaining the snapshot. A storage area of the second logical volume is allocated in chunk units to the first logical volume and a tendency of order to delete snapshots is judged when the chunks have been completely used up. If there is a tendency to delete the snapshots in their acquisition order, a new chunk is allocated to the first logical volume and a storage area in that chunk is determined to be a save location of the old data. If there is a tendency to delete the snapshots randomly, an unused storage area in a chunk already allocated to the first logical volume is determined to be the save location of the old data.