The redundancy calculation manner in the hierarchical type redundant storage system, RAID which is jointed to the RAID

摘要

PPROBLEM TO BE SOLVED: To provide a redundancy calculation method for easily calculating redundancy from the viewpoint of a virtual disk, for a hierarchical redundancy storage system, and to provide a RAID (Redundant Array of Inexpensive Disks) device and a program. PSOLUTION: Redundancy is set in a disk device and the RAID device. Disk devices as many as the number of the redundancy of the RAID device are set in a redundant disk in the ascending order of redundancy, and the other disk devices are set in a data disk. The sum of the redundancy of each disk device set in the redundant disk, the minimum redundancy among the disk devices set in the data disk, and the redundancy of the RAID device is defined as the redundancy of the virtual disk in the RAID disk. The redundancy of the virtual disk is stored. When a fault of the disk device is detected, the redundancy is calculated again. The RAID device is used in the hierarchical redundancy storage system. PCOPYRIGHT: (C)2010,JPO&INPIT