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US 7,827,351 B2Granted
Storage system having RAID level changing function
AssigneeHitachi, Ltd.
InventorsMichio Suetsugu, Yoshinori Okami, Takao Sato
Life of this patent
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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.
Claims18
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,
- wherein the second RAID level has higher fault tolerance than the first RAID level, and
- wherein the controller changes the RAID level of the RAID group from the first RAID level to the second RAID level in use of the selected spare storage device when an error rate of a certain member storage device of the not less than two member storage devices exceeds a first threshold.
2 more elements
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 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.
1 more element
Dependencies are inferred from the claim text.