STORAGE SYSTEM AND METHOD OF EXECUTING COMMANDS BY CONTROLLER

• US 20120297155A1
• Filed: 08/02/2012
• Published: 11/22/2012
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: YAMAGUCHI, Yasuhiko, GOTOH, Youichi
• Granted Patent: US 8,694,741 B2
• Time in Patent Office: Days
• US Class Current: 711/158
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A storage subsystem capable of processing time-critical control commands while suppressing deterioration of the system performance to a minimum. When various commands are received in a multiplex manner via the same port from plural host devices, the channel adapter of the storage subsystem extracts commands of a first kind from the received commands. Then, the adapter executes the extracted commands of the first kind with high priority within a given unit time until a given number of guaranteed activations is reached. At the same time, commands of a second kind are enqueued in a queue of commands. After the commands of the first kind are executed as many as the number of guaranteed activations, the commands of the second kind are executed in the unit time.

Claims

1. A storage system, comprising:

a plurality of storage devices; and

a controller configured to execute a priority command for the plurality of storage devices upon a quantity of priority commands to be executed during a predetermined time period being less than or equal to a predetermined value, add a non-priority command to a non-priority command queue, and execute the non-priority command in the non-priority command queue for the plurality of storage devices following execution of the priority command during the predetermined time period.

2. A storage system as set forth in claim 1, wherein the priority command is one of an inquiry command and a read capacity command, and wherein the non-priority command is an I/O command.

3. A storage system as set forth in claim 1, wherein the controller determines whether each received command is a priority command based on priority command information that defines attributes of commands, and wherein the priority command information includes a logical block address indicating a specified storage region in the storage drives.

4. A storage system as set forth in claim 3, wherein, if a received command designates the specified storage region, the controller determines the received command to be a priority command.

5. A storage system as set forth in claim 3, wherein the controller creates the priority command information based on a priority command-setting request sent from a management apparatus.

6. A storage system as set forth in claim 1, wherein a host computer coupled to the controller includes a plurality of virtual machines, and wherein the virtual machines send a plurality of commands to the controller.

7. A method of executing commands for a plurality of storage drives of a storage system by a controller within the storage system, the method comprising:

executing a priority command for the plurality of storage devices upon a quantity of priority commands to be executed during a predetermined time period being less than or equal to a predetermined value;

adding a non-priority command to a non-priority command queue; and

executing the non-priority command in the non-priority command queue for the plurality of storage devices following execution of the priority command during the predetermined time period.

8. A method as set forth in claim 7, wherein the priority command is one of an inquiry command and a read capacity command, and wherein the non-priority command is an I/O command.

9. A method as set forth in claim 7, further comprising determining whether each command received by the controller is a priority command based on priority command information that defines attributes of commands, and wherein the priority command information includes a logical block address indicating a specified storage region in the storage drives.

10. A method as set forth in claim 9, further comprising, if a received command designates the specified storage region, determining the received command to be a priority command.

11. A method as set forth in claim 9, further comprising creating the priority command information based on a priority command-setting request sent from a management apparatus.

12. A method as set forth in claim 7, wherein a host computer coupled to the controller includes a plurality of virtual machines, and wherein the virtual machines send a plurality of commands to the controller.