Storage system

Abstract

A storage group configured by a plurality of storage devices is configured by a plurality of storage sub-groups, and the respective storage sub-groups are configured from two or more storage devices. A sub-group storage area, which is the storage area of the respective storage sub-groups, is configured by a plurality of rows of sub-storage areas. A data set, which is configured by a plurality of data elements configuring a data unit, and a second redundancy code created on the basis of this data unit, is written to a row of sub-storage areas, a compressed redundancy code is created on the basis of two or more first redundancy codes respectively created based on two or more data units of two or more storage sub-groups, and this compressed redundancy code is written to a nonvolatile storage area that differs from the above-mentioned two or more storage sub-groups.

1 . A storage system, comprising:
 a storage group configured by a plurality of storage devices; and   a write controller that controls writing to the storage group, the storage group being configured from a plurality of storage sub-groups;   wherein the respective storage sub-groups being configured from two or more storage devices of the plurality of storage devices;   wherein the plurality of storage sub-groups being configured from a plurality of first type storage sub-groups and a plurality of second type storage sub-groups;   wherein the two or more storage devices, which configure the respective second type storage sub-groups, being storage devices that respectively constitute components of the plurality of first type storage sub-groups, and therefore, the respective storage devices that configure the storage group constituting components of both any of the plurality of first type storage sub-groups, and any of the plurality of second type storage sub-groups;   wherein respective first type sub-group storage areas, which are respective storage areas of the respective first type storage sub-groups, being configured from a plurality of rows of first type sub-storage areas;   wherein the row of first type sub-storage areas spanning the two or more storage devices configuring the first type storage sub-group, and being configured from two or more first type sub-storage areas corresponding to these two or more storage devices;   wherein the respective second type sub-group storage areas, which are the respective storage areas of the respective second type storage sub-groups, being configured from a plurality of rows of second type sub-storage areas;   wherein the row of second type sub-storage areas spanning the two or more storage devices that configure the second type storage sub-group, and being configured from two or more second type sub-storage areas corresponding to these two or more storage devices;   wherein a first type data unit and a second type data unit existing as data units, the data being of a prescribed size, and made up of a plurality of elements;   wherein the first type data unit is configured from a plurality of data elements;   wherein the second type data unit is configured from one data element of each of the plurality of first type data units; and   wherein the write controller:   writes (W 1 ) a data set, which comprises a plurality of data elements configuring the first type data unit and a first redundancy code created based on the plurality of data elements, to the row of first type sub-storage areas; and   writes (W 2 ) a second redundancy code, which is created based on the second type data unit that is present in the row of second type sub-storage areas, to a free second type sub-storage area in the row of second type sub storage areas,   wherein the respective second type storage sub-groups are RAID groups corresponding to RAID 4.