STORAGE SYSTEM HAVING RAID LEVEL CHANGING FUNCTION
First Claim
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1. A storage system, comprising:
- a plurality of storage devices having not less than two member storage devices which are storage devices provided as members of a RAID group, and either one or a plurality of spare storage devices which are spare storage devices that are not members of the RAID group; and
a controller for changing a RAID level of the RAID group from a first RAID level to a second RAID level in use of a spare storage device selected from among the either one or a plurality of spare storage devices.
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Abstract
A plurality of storage devices, provided in a storage system, comprise not less than two member storage devices, which are storage devices provided as members of a RAID group, and a spare storage device, which is not a member of the RAID group. A controller, provided in the storage system, uses the spare storage device to carry out the changing of the RAID level of the RAID group from a first RAID level to a second RAID level.
35 Citations
20 Claims
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1. A storage system, comprising:
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a plurality of storage devices having not less than two member storage devices which are storage devices provided as members of a RAID group, and either one or a plurality of spare storage devices which are spare storage devices that are not members of the RAID group; and a controller for changing a RAID level of the RAID group from a first RAID level to a second RAID level in use of a spare storage device selected from among the either one or a plurality of spare storage devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 20)
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18. A storage system, comprising:
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not less than two storage devices which constitute a RAID group; and a controller having a cache memory, wherein the controller is constituted so as to receive a write command from outside of the storage system, write an information element based on this write command to the cache memory, and, in this case, report write-completion to an outside unit, and, asynchronously thereto, write this information element to the RAID group, and if the RAID level of the RAID group is in a process of being changed, the controller holds off writing this information element to the RAID group, and writes this information element to the RAID group subsequent to the end of the RAID level change.
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19. A storage system comprising:
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a plurality of storage devices having not less than two member storage devices which are storage devices provided as members of a RAID group, and a spare storage device which is not a member of this RAID group; and a controller for carrying out an information backup process, which writes an information element stored in a certain member storage device to the spare storage device when an error rate of this certain member storage device of the not less than two member storage devices exceeds a second threshold, wherein the controller changes a RAID level of the RAID group from a first RAID level to a second RAID level, which features higher fault tolerance than the first RAID level, prior to carrying out the information backup process.
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Specification