JP2856054B2 - Disk array device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device (hereinafter, referred to as a disk array device) configured by arranging a plurality of disks and distributing and storing data, and in particular, has a function of increasing the disk capacity during operation. A disk array device having the same.

[0002]

2. Description of the Related Art In a conventional disk array device, in order to increase the disk capacity during operation of the device, the disk drive in use is replaced with a disk drive having a larger capacity to increase the disk capacity. Was realized. In this conventional technique, in order to replace the original disk drive, the contents of the disk drive are temporarily evacuated to a storage medium other than the relevant disk array device, and after the expansion work is completed, the redundancy information is set in the entire disk array. Restore the saved data.

As another method, there is a method in which another disk array device is added and the disk device is properly used by an application program.

[0004]

In the first prior art, the original disk drive is replaced in order to increase the capacity of the disk array device. After the extension work is completed, the redundant information is set in the entire disk array, and the saved data is restored. That is, data migration using another storage medium is required. Further, during the data migration, the operation of another application program that accesses the data must be interrupted.

In another conventional technique, since data is divided into a plurality of disk arrays, the continuity of data is lost, and an application program accessing the original disk array device performs processing for selectively using the disk device. Is required, and it becomes necessary to change the data access portion of the application program.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a disk array device according to the present invention uses a disk drive group having a plurality of disk drives and an error recovery for writing data to the disk drive group. Write control means for generating error repair information as the information of the disk drive, read control means for checking the occurrence of an error with respect to the read data from the disk drive group and correcting the error, and decoding an access request from an external device. Interface means for calculating which of the plurality of disk drives the access request is an access request to.

Further, the write control means writes an initial value to the disk drive.

[0008] Further, the interface means stores an arrangement order of data stored in the disk drive group.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the disk array device of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a disk array device 100 according to an embodiment of the present invention includes a disk drive group 200 including a plurality of disk drives, and a write buffer means for holding write data to the disk drive group 200. 120 and an error recovery information generating means 130 for generating error recovery information as information for error recovery relating to data written to the disk drive group 200
A read buffer means 140 for holding data read from the disk drive group 200, an error check means 150 for checking the occurrence of an error in the data held in the read buffer means 140, and Interface means 110 for exchange, and disk array configuration information storage means 17 for storing configuration information in the disk array device 100
0, and a logical disk information storage unit 180 for storing disk specifications when the disk array device 100 is regarded as one logical disk.

FIG. 2 shows the order of data arrangement in a disk array according to a RAID4 configuration.
Here, RAID4 is one of the configurations of a disk array, in which data for a disk drive group is divided in block units, the divided data is distributed and stored in each drive of the disk drive group, and the parity data is stored. It is a configuration to store in another drive, for example, "A Case f
or Redundant Arrays of Inexpensive Disks (RAID), University of California, Berkeley, Department of Computer Science (EESC), Report No. UCB / CSD / 87/3
91 ". Disk drives # 4-1 to # 4-m include data D4-11 to D4-mn, parity drive #P includes parities DP-1 to DP-n, and additional drive # 5-1. The data D5-11 is stored in ~ # 5-k.
~ D5-kn. Here, m represents the number of disk drives constituting the original disk array minus one, n represents the maximum number of blocks of each disk drive, and k represents the number of additional disk drives.

Each data of the original disk drive group 210 has the following equation (1) between the data of the parity drive #P and the data at the same position of the remaining disk drives. Here, xor represents exclusive OR.

D4-1ixor D4-2ixor D4-3ixor... D4-mi = DP-i Formula (1) (1 ≦ i ≦ n) The relationship of this formula (1) is read by the read buffer means 140. Error checking means 150 for checking the validity of the output data
This is used by the error recovery information generating means 130 when writing data when one disk drive fails.

Next, a procedure for adding a disk drive in the above-described embodiment of the disk array device of the present invention will be described.

Referring to FIG. 3, after the additional disk drive group 220 is connected (step 301), the interface means 110 is provided from outside the disk array device 100.
When a disk expansion request is received, the expansion processing starts. When the interface unit 110 transmits an expansion request to the error recovery information generation unit 130, the error recovery information generation unit 130 generates initial data "0" and writes the initial data "0" to the write buffer unit. Then, the initial data “0” is written to each disk drive of the additional disk drive group 220 (step 302). The initial data is set to "0" because if "0", the following relationship is satisfied in the added disk array device.

D4-1ixor D4-2ixor D4-mixor D5-1ixor D5-ki = DP-i Equation (2) (1 ≦ i ≦ n) Therefore, the relationship of Equation (2) is broken. If not, any combination of data may be used as the initial data.

Even while the initial data is being written to the additional disk drive group 220, for example, "
If 0 "etc. are used, the original disk drive group 2
Since it is not necessary to use the disk drive 10, it is possible to allow another application program to access the original disk drive group 210. However, at this point, the additional disk drive group 220 has not been accessed yet, and the capacity of the disk array device 100 has not increased. The disk drives accessible from other application programs are limited to those of the original disk drive group 210.

When the initial data setting for the additional disk drive 220 is completed, the interface means 110 changes the disk array configuration information to the disk array configuration information storage means 170 (step 303). The disk array configuration information includes the disk drive group 2
00, and the order of data stored in each disk drive. For example, FIG.
In the disk array configuration information before expansion, the number of disk drives is (m + 1) and the logical data order is “D4-11, D4-21,..., D4-m1, D4-12,. -m
2, ..., D4-1n, ..., D4-mn ". In addition, the disk array configuration information after expansion in FIG. 2 indicates that the number of disk drives is (m + 1 +
k) units, and the logical data order is “D4-11, D4-21,
..., D4-m1, D4-12, ..., D4-m2, ..., D4-1n, ..., D
4-mn, D5-11, ..., D5-1n, ..., D5-k1, ..., D5-kn "
It includes that it is an arrangement like.

When the change of the disk array configuration information is completed, the interface means 110 changes the logical disk information to the logical disk information storage means 180 (step 304). The logical disk information includes disk specifications when the entire disk array device is regarded as one disk device, and includes, for example, a physical block length, a last block address, disk use information, and disk space information. Contains. When the change of the logical disk information is completed, the additional disk drive group 220 can be accessed as a part of the disk array device.

Next, a description will be given of a procedure for calculating a disk drive position when an access request by a logical address is made in the above-described embodiment of the disk array apparatus of the present invention.

Referring to FIG. 4, for data D-j for which an access request has been made, the interface means 110 refers to the disk array configuration information and performs the following procedure.
It is determined which disk drive in the disk drive group 200 exists. Here, j means a logical address starting from the first address.

First, x1 and x2 are obtained by the following equation (step 401).

X1 ← INT ｛(j−1) / m｝ ... Formula (3) x2 ← MOD ｛(j−1), mm where INT represents an integer part of {(j−1) / mm. , MOD represents the remainder of dividing (j−1) by m.

As a result, if x1 <n (step 402), the disk drive where the data D-j exists is # 4- (x2 + 1) and the position is D4- (x2 + 1). (x1 + 1) (step 403). If x1 ≧ n is satisfied (step 403), y1 and y2 are further obtained from the following equation (step 404).

Y1 ← INT ｛(j−m × n−1) / n｝ Equation (4) y2 ← MOD ｛(j−m × n−1), n｝ As a result, data Dj exists. The disk drive is # 5- (y1 + 1), and the position can be obtained as D5- (y1 + 1) (y2 + 1) (step 405).

[0026]

As described above, according to the present invention, when adding a disk drive to a disk array device, it is not necessary to migrate already stored data, and the physical data arrangement order is taken into consideration. There is an effect that it is possible to access without performing.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a disk array device according to the present invention.

FIG. 2 is a diagram showing an arrangement of data in each disk drive according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a procedure for adding a disk drive according to an embodiment of the present invention.

FIG. 4 is a diagram showing a procedure for obtaining a disk drive position from a logical address in one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 110 interface means 120 write buffer means 130 error repair information generating means 140 read buffer 150 error checking means 170 disk array configuration information storage means 180 logical disk information storage means 200 disk drive group 210 original disk drive group 220 additional disk drive group

Claims (2)

(57) [Claims] 1. A disk array device having a disk drive group composed of a plurality of physical disk drives and distributing and storing data in the plurality of physical disk drives, for recovering an error relating to data written to the disk drive group. Write control means for generating error correction information as the information of the disk drive and controlling the writing of data and error correction information to the disk drive group; and Read control means for restoring data by means of a logical drive, logical disk information storage means for storing the specifications of a logical disk when the entire disk drive group is regarded as one logical disk, and one logical disk for storing the entire disk drive group Access from outside Interface means for converting information into physical storage position information of each disk drive of the disk drive group; logical means of data written to each physical disk drive when the entire disk drive group is regarded as one logical disk A disk array configuration information storage unit for storing order information indicating an order, wherein the interface unit converts the external access position information to the disk based on the order information stored in the disk array configuration information storage unit. A disk array device for converting physical storage location information of the physical disk drives of a drive group. 2. When adding at least one physical disk drive to the disk drive group, the write control means writes an initial value that does not change the error correction information to the at least one physical disk drive. The disk array device according to claim 1.