Patent ID: 8732422
Filing Date: 2014-05-20
Classification: G06F

Abstract:
1. A storage apparatus comprising: one or more storage devices for providing a storage area; and a controller for creating first and second logical volumes in the storage area provided by the one or more storage devices, providing the created first logical volume to a host computer, and obtaining a snapshot of the first logical volume when needed, wherein when data is written to the first logical volume after obtaining the snapshot, the controller saves data, to which the relevant data has not been written yet, as old data to the second logical volume when needed; and wherein the controller allocates a storage area of the second logical volume in a unit of a chunk of a specified size to the first logical volume and stores the old data, which is saved from the first logical volume, in the chunk allocated to the first logical volume; and when the controller has completely used up the chunk allocated to the first logical volume, it judges a tendency of order to delete the snapshot; and if there is a tendency to delete the snapshot in acquisition order, the controller allocates a new chunk to the first logical volume and determines a storage area in that chunk to be a save location of the old date saved from the first logical volume; and if there is a tendency to delete the snapshot randomly, the controller searches for a storage area, in which the old data is not stored, in the chunk already allocated to the first logical volume, determines the storage area found as a result of the search to be the save location of the old data saved from the first logical volume, and stores the old data, which is saved from the first logical volume next time, in the storage area determined to be the save location of the old data.