RAID CONTROL APPARATUS AND RAID SYSTEM

• US 20100262775A1
• Filed: 06/22/2010
• Published: 10/14/2010
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Daikokuya, Hidejirou, Ito, Mikio, Ikeuchi, Kazuhiko
• Granted Patent: US 8,190,817 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: G06F 2211/1059 Parity-single bit-RAID5, i.e. RAID 5 implementations

Abstract

A RAID system performs host I/O processing during RAID formatting of a plurality of physical disk drives. The controller executes sequential format processing and one-point format processing. A RAID format writing size (SFS) for sequential format processing is set larger than a RAID format writing size (OFS) for one-point format processing. Delay of host I/O processing is reduced, so that the time required for RAID formatting can be shortened.

Claims

1. A RAID control apparatus which receives and processes an I/O request from a host before completing the writing of a RAID format pattern to a plurality of physical disk drives, comprising:

a channel adapter for controlling interface with the host;

a control unit which, when an I/O request arrives from the host and a range requested by the I/O request has not been RAID-formatted, executes a one-point format processing to write the RAID format pattern in an area of the physical disk drive that corresponds to the range requested by the I/O request, and a sequential format processing to write the RAID format pattern sequentially from a first logical block address to a last logical block address in a RAID configuration constituted by the plurality of physical disk drives; and

a device adapter which is connected to the plurality of physical disk drives and controls interface with the plurality of physical disk drives,

wherein the control unit executes the sequential format processing by setting a RAID format writing size of one cycle of the sequential format processing to be larger than the RAID format writing size of the one-point format processing.

2. The RAID control apparatus according to claim 1, wherein the control unit inquires a capacity and a track size of the plurality of physical disk drives constituting the RAID, and determines the RAID format writing size of the one cycle of the sequential format processing based on the capacity and the track size.

3. The RAID control apparatus according to claim 2, wherein the control unit executes the sequential format processing by setting the RAID format writing size of one cycle of the sequential format processing to a capacity of one round of a track of the physical disk drive.

4. The RAID control apparatus according to claim 1, wherein the control unit judges whether or not the area RAID-formatted by the one-point format processing exists in an area specified by the RAID format writing size before starting one cycle of the sequential format processing, and when the area RAID-formatted by the one-point format processing exists in the area specified by the RAID format size of the one cycle of the sequential format processing, executes the sequential format processing after changing the RAID format writing size so as to cross over the area RAID-formatted by the one-point format processing.

5. The RAID control apparatus according to claim 1, wherein the control unit starts the sequential format processing after detecting that an I/O request from the host has not arrived for a predetermined time.

6. The RAID control apparatus according to claim 4, wherein the control unit has a RAID format management table for managing a progress state of the RAID formatting,

and the control unit judges whether or not the area RAID-formatted by the one-point format processing exists in an area specified by the RAID format size with reference to the RAID format management table.

7. The RAID control apparatus according to claim 1, wherein the control unit has a pointer for storing a first area of the sequential format processing, and

The control unit determines an area specified by the RAID format writing size in the sequential format processing with reference to the pointer.

8. The RAID control apparatus according to claim 2, wherein the control unit has a buffer which stores RAID format pattern when the sequential format processing, and

The control unit compares a RAID format writing size of the one cycle of the sequential format processing that is determined based on the capacity and the track size, with a capacity of the buffer, and sets a RAID format writing size that is smaller than the determined RAID format writing size when the RAID format writing size exceeds the capacity of the buffer.

9. The RAID control apparatus according to claim 1, wherein the control unit creates RAID format pattern in a cache memory, executes the one-point format processing, and creates the RAID format pattern in a buffer and executes the sequential format processing.

10. The RAID control apparatus according to claim 2, wherein the control unit inquires a capacity and a track size of the plurality of physical disk drives constituting the RAID, and determines the RAID format writing size of the one cycle of the sequential format processing based on the RAID configuration, the capacity, and the track size.

11. A RAID system which receives and processes an I/O request from a host before completing the writing of a RAID format pattern to a plurality of physical disk drives, comprising:

the plurality of physical disk drives;

a channel adapter for controlling interface with the host;

a control unit which, when an I/O request arrives from the host and a range requested by the I/O request has not been RAID-formatted, executes a one-point format processing to write the RAID format pattern in an area of the physical disk drive that corresponds to the range requested by the I/O request, and a sequential format processing to write the RAID format pattern sequentially from a first logical block address to a last logical block address in a RAID configuration constituted by the plurality of physical disk drives; and

a device adapter which is connected to the plurality of physical disk drives and controls interface with the plurality of physical disk drives,

wherein the control unit executes the sequential format processing by setting RAID format writing size of one cycle of the sequential format processing to be larger than the RAID format writing size of the one-point format processing.

12. The RAID system according to claim 11, wherein the control unit inquires a capacity and a track size of the plurality of physical disk drives constituting the RAID, and determines the RAID format writing size of the one cycle of the sequential format processing based on the capacity and the track size.

13. The RAID system according to claim 12, wherein the control unit executes the sequential format processing by setting the RAID format writing size of one cycle of the sequential format processing to a capacity of one round of a track of the physical disk drive.

14. The RAID system according to claim 11, wherein the control unit judges whether or not the area RAID-formatted by the one-point format processing exists in an area specified by the RAID format size before starting one cycle of the sequential format processing, and when the area RAID-formatted by the one-point format processing exists in the area specified by the RAID format size of the one cycle of the sequential format processing, executes the sequential format processing after changing the RAID format writing size so as to cross over the area RAID-formatted by the one-point format processing.

15. The RAID system according to claim 11, wherein the control unit starts the sequential format processing after detecting that an I/O request from the host has not arrived for a predetermined time.

16. The RAID system according to claim 14, wherein the control unit has a RAID format management table for managing a progress state of the RAID formatting, and

the control unit judges whether or not the area RAID-formatted by the one-point format processing exists in an area specified by the RAID format writing size with reference to the RAID format management table.

17. The RAID system according to claim 11, wherein the control unit has a point for storing a first area of the sequential format processing, and

the control unit determines an area specified by the RAID format writing size in the sequential format processing with reference to the pointer.

18. The RAID system according to claim 12, wherein the control unit has a buffer which stores the RAID format pattern when the sequential format processing, and

the control unit compares a RAID format writing size of the one cycle of the sequential format processing that is determined based on the capacity and the track size, with a capacity of the buffer, and sets a RAID format writing size that is smaller than the determined RAID format writing size when the RAID format writing size exceeds the capacity of the buffer.

19. The RAID system according to claim 11, wherein the control unit creates the RAID format pattern in a cache memory, executes the one-point format processing, and creates the RAID format pattern in a buffer and execute the sequential format processing.

20. The RAID system according to claim 12, wherein the control unit inquires a capacity and a track size of the plurality of physical disk drives constituting the RAID, and

the control unit determines a RAID format writing size of the one cycle of the sequential format processing based on the RAID configuration, the capacity, and the track size.