Storage apparatus and load distribution method

• US 20080184255A1
• Filed: 01/04/2008
• Published: 07/31/2008
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Watanabe, Koji, Sugimoto, Sadahiro
• Granted Patent: US 8,161,490 B2
• Time in Patent Office: Days
• US Class Current: 718/105
• CPC Class Codes: G06F 2209/5022 Workload threshold
• CPC Class Codes: G06F 9/505 considering the load

Abstract

A storage apparatus having plural control processors that interpret and process requests sent from a host computer includes a distribution judgment unit for judging, after a control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from the control processor that received the request to another control processor, and a control processor selection unit for selecting an allocation target control processor if the distribution judgment unit judges to allocate the processing to another control processor.

Claims

1. A storage apparatus having plural control processors that interpret and process a request sent from a host computer, the storage apparatus comprising:

a distribution judgment unit for judging, after a control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from that control processor to another control processor; and

a control processor selection unit for selecting an allocation target control processor if the distribution judgment unit decides to allocate the processing to another control processor.

2. The storage apparatus according to claim 1, wherein the distribution judgment unit judges whether or not to allocate the processing relevant to the request to another channel processor based on the total number of requests received by the control processor and the number of allocations of processing relevant to the requests to another control processor during a prescribed time cycle.

3. The storage apparatus according to claim 2, wherein the distribution judgment unit decides the total number of allocations of the processing relevant to the request to another control processor based on the average response time for the processing in the control processor that received the request during a prescribed time cycle.

4. The storage apparatus according to claim 3, wherein the distribution judgment unit calculates the number of allocations of the processing relevant to each type of request to another control processor based on the number of received requests of each type and the total number of allocations of the requests to another control processor.

5. The storage apparatus according to claim 3, wherein the distribution judgment unit prohibits allocation of the processing from another control processor to the control processor that received the request if the average response time for the processing in the control processor that received the request exceeds a first threshold, and makes the control processor that received the request resume accepting allocation from another control processor if the average response time for the processing in another control processing exceeds a second threshold.

6. The storage apparatus according to claim 1, wherein the control processor selection unit selects the allocation target control processor from among the control processors other than the control processor that received the request, in the order of shorter average response time for the processing.

7. The storage apparatus according to claim 6, wherein the control processor selection unit does not select again any control processor already selected once before until all control processors that can be allocation targets have been selected.

8. A load distribution method for a storage apparatus having plural control processors that interpret and process a request sent from a host computer, the method comprising:

a first step of judging, after a control processor receives a request sent from the host computer, whether or not to allocate processing relevant to the request from the control processor that received the request to another control processor; and

a second step of selecting an allocation target control processor if the processing allocation is decided upon in the first step.

9. The load distribution method according to claim 8, wherein in the first step, whether or not to allocate the processing relevant to the request to another channel processor is determined based on the total number of requests received by the control processor and the number of allocations of the processing relevant to the requests to another control processor during a prescribed time cycle.

10. The load distribution method according to claim 9, wherein in the first step, the total number of allocations of the processing relevant to the requests to another control processor is determined based on average response time for the processing in the control processor that received the request during a prescribed time cycle.

11. The load distribution method according to claim 10, wherein in the first step, the number of allocations of the processing relevant to each type of request to another control processor is calculated based on the number of received requests of each type and the total number of allocations of the requests to another control processor.

12. The load distribution method according to claim 10, wherein in the first step, allocation of the processing from another control processor is prohibited if the average response time for the processing in the control processor that received the request exceeds a first threshold, and acceptance of allocation of the processing from another control processor is resumed if the average response time for the processing in another control processor exceeds a second threshold.

13. The load distribution according to claim 8, wherein in the second step, the allocation target control processor is selected from among the control processors other than the control processor that received the request, in the order of shorter average response time for the processing.

14. The load distribution method according to claim 13, wherein in the second step, any control processor already selected once before is not selected again until all control processors that can be allocation targets have been selected.