Method for changing raid-level in disk array subsystem

Claim 2

A disk array subsystem comprising: a plurality of drives for storing data; and a controller for controlling said drives and allocating a plurality of storage areas to said drives, wherein when implementing redundancy by recording or writing same data in said storage areas, said controller allocates a first storage area to at least one of said storage areas such that a plurality of data blocks and a parity block for storing parity data generated from said data blocks are distributed over said drives in said at least one storage area.

Claim 3

The disk array subsystem according to claim 1 , wherein when changing from implementing redundancy by recording or writing same data in said storage areas to implementing redundancy by distributing a plurality of data blocks and a parity block for storing parity data generated from said data blocks over said drives in said at least one storage area, said controller stores parity data generated from said plurality of data blocks in said parity block in said first storage area and distributes said parity block and said data blocks over said drives in said first storage area, thereby implementing redundancy while deleting data in other storage areas in which the same data are stored.

Claim 4

The disk array subsystem according to claim 2 , wherein data blocks that are used for generating the parity data to be stored in said parity block in said first storage area have been stored in the same drive in said other storage areas as one in which said parity block is provided in said first storage area.

Claim 5

The disk array subsystem according to claim 3 , wherein said controller generates parity data to be stored in said parity block in said first storage area from data stored in the same drive in said other storage areas as one in which said parity block in said first storage area is provided.

Claim 6

The disk array system according to claim 4 , wherein the drive which has said parity block in said first storage area generates parity data to be stored in said parity block from data stored in said other storage areas in said drive.

Claim 7

A disk array subsystem having: a plurality of drives for storing data; and a controller for controlling said drives and allocating a plurality of storage areas to said drives, wherein said disk array subsystem involves two kinds of data, a first kind of data being data going through redundancy processing by which said data is stored in said storage areas, while a second kind of data going through different redundancy processing by which a plurality of data and parity data generated from said data are stored in said plurality of drives in a storage area, wherein a first storage area, which is one of said storage areas which are for storing same data for redundancy purposes, has a block for storing parity data generated from a plurality of blocks of data, and wherein when said controller changes a method of executing redundancy processing from a method of storing same data in a plurality of storage areas to a method of storing a plurality of data and parity data generated therefrom in said drives in a storage area, said controller uses said first storage area as a storage area for executing the redundancy processing based on parity data. 7 .The disk array subsystem according to claim 6 , wherein the method executing redundancy processing by storing same data in a plurality of storage areas is RAID 1 , while the method of executing redundancy processing by storing a plurality of data and parity data generated from said data in said drives in a storage area is RAID 5 .

Claim 8

The disk array subsystem according to claim 6 , wherein when said controller changes the method of executing redundancy processing from a method of storing same data in a plurality of storage areas to a method of storing a plurality of data and parity data generated therefrom in said drives in a storage area, said controller generates said parity data from said plurality of data, stores the generated data in said parity block, and deletes data in other storage areas which have stored therein the same data as that stored in said first storage area.

Claim 9

The disk array subsystem according to claim 8 , wherein those data blocks that are used for generating the parity data to be stored in said parity block in said first storage area have been stored in the same drive in said other storage areas as one in which the same drive in said other storage areas as one in which said parity block is provided in said first storage area.

Claim 10

The disk array subsystem according to claim 9 , wherein said controller generates parity data to be stored in said parity block in said first storage area from data stored in the same drive in said other storage areas as one in which said parity block in said first storage area is provided.

Claim 11

The disk array subsystem according to claim 9 , wherein the drive which has said parity block in said first storage area generates parity data to be stored in said parity block from data stored in said other storage areas in said drive.

Claim 12

The disk array subsystem according to claim 6 , wherein said controller changes the method of executing redundancy processing based on an instruction from a host apparatus to be connected to said controller.

Claim 13

The disk array subsystem according to claim 6 , wherein said controller changes the method of executing redundancy processing based on access frequency information given by a host apparatus to be connected to said controller.

Claim 14

A disk array subsystem having: a plurality of drives for storing data; a controller for controlling said plurality of drives and allocating a plurality of storage areas to the plurality of drives, wherein said subsystem involves two kinds of data, a first kind of data being data which goes through redundancy processing by which same data are stored in said storage areas, while a second kind of data being data which goes through redundancy processing by which a plurality of data and parity data generated from said plurality of data are stored in said drives in a storage area, wherein of first and second storage areas for storing same data for redundancy purpose, the first storage area has a block for storing parity data generated from a plurality of blocks of data, and wherein when said controller changes a method of executing redundancy processing from a method of storing same data in a plurality of storage areas to a method of storing a plurality of drives in a storage area, said controller uses said first storage area as a storage area for executing the redundancy processing based on parity data.

Claim 15

A disk array subsystem having: a plurality of drives for storing data; a controller for controlling said plurality of drives and allocating a plurality of storage areas to the plurality of drives, wherein said subsystem involves two kinds of data, a first kind of data being data which goes through redundancy processing by which same data are stored in said storage areas, while a second kind of data being data which goes through redundancy processing by which a plurality of data and parity data generated from said plurality of data are stored in said drives in a storage area, wherein of first and second storage areas for storing same data for redundancy purpose, the first storage area has a block for storing parity data generated from a plurality of blocks of data, and wherein when said controller changes a method of executing redundancy processing from a method of storing same data in a plurality of storage areas to a method of storing a plurality of drives in a storage area, said controller uses said first storage area as a storage area for executing the redundancy processing based on parity data.

Claim 16

The disk array subsystem according to claim 14 , wherein the method of redundancy processing by storing same data in a plurality of storage areas is RAID 1 , while the method of redundancy processing method by storing a plurality of data and parity data generated from said plurality of data in said plurality of drives in a storage area is RAID 5 .

Claim 17

The disk array subsystem according to claim 14 , wherein when said controller changes the method of executing redundancy processing from the method of storing same data in a plurality of storage areas to the method of storing same data in a plurality of storage areas to the method of storing a plurality of data and parity data generated therefrom in said plurality of drives in a storage area, said controller generates said parity data from said plurality of data, stores the generated said parity data in said parity block, and deletes data in said second storage area which has stored therein the same data as that stored in said first storage area.

Claim 18

The disk array subsystem according to claim 16 , wherein those data blocks that are used for generating the parity data to be stored in said parity block in said first storage area have been stored in the same drive in said second storage areas as one in which said parity block is provided in said first storage area.

Claim 19

The disk array subsystem according to claim 17 , wherein said controller generates parity data to be stored in said parity block in said first storage area from data stored in the same drive in said second storage area as one in which said parity block in said first storage area is provided.

Claim 20

The disk array subsystem according to claim 17 wherein the drive which has said parity block in said first storage area generates parity data to be stored in said parity block from data stored in said second storage area in said drive.

Claim 21

The disk array subsystem according to claim 14 , wherein said controller changes the method of executing redundancy processing based on an instruction from a host apparatus to be connected to said controller.

Claim 22

The disk array subsystem according to claim 14 , wherein said controller changes the method of executing redundancy processing based on an instruction given by a service processor to be connected to said controller.

Claim 23

The disk array subsystem according to claim 14 , wherein said controller changes the method of executing redundancy processing based on access frequency information given by a host apparatus to be connected to said controller.