Storage device

Patent metadata

Field	Value
Publication number	US-10296429-B2
Application number	US-201415126428-A
Country	US
Kind code	B2
Filing date	Jul 25, 2014
Priority date	Jul 25, 2014
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A storage subsystem comprises one or more volumes, and multiple nodes having multiple control packages interconnected via an intra-node communication path, wherein the control packages of different nodes are interconnected via an inter-node communication path having a lower transmission path capacity than the intra-node communication path. When the host computer accesses a volume, access is enabled via any of at least two or more control packages out of the multiple control packages, and the priority for issuing access requests to the relevant volume is determined in each of the control packages. When the storage subsystem detects failure, it changes the priorities determined for the control packages according to the failure occurrence portion, and notifies the same to the host computer. The host computer determines the control package being the issue destination of the access request based on the notified priority.

First claim

The invention claimed is:

1. A storage subsystem comprising:
a plurality of control nodes for processing requests from a host computer, wherein the plurality of control nodes includes a first control node and a second control node;
a plurality of control packages that each have a priority determined for issuing an access request from the host computer, wherein each of the plurality of control packages include a processor, a memory, and a port for receiving accesses from the host computer;
a first subset of the plurality of control packages that includes respective control packages that are mutually interconnected within the first control node via a respective first communication path;
a second subset of the plurality of control packages, wherein the second subset includes respective control packages that are mutually interconnected within the second control node via a respective first communication path,
a second communication path that interconnects the first subset with the second subset wherein the second communication path has a lower performance than each respective first communication path;
a plurality of storage volumes that are communicatively coupled to the plurality of control packages, wherein the host computer accesses the plurality of storages volumes via one or more of the plurality of control packages; and
a plurality of owners that are each associated with a respective storage volume from the plurality of storage volumes,
wherein each respective owner is a particular control package from the plurality of control packages that is configured to process an I/O request arriving from the host computer to the respective storage volume;
wherein in response to detection of a failure in the storage subsystem, the storage subsystem:
selects a new owner of a particular volume according to a failure occurrence section, wherein a different owner is selected when the failure in the storage subsystem is detected in the respective owner then when the failure is detected an access path between the host computer and the respective owner,
raises the priority of the new owner to a highest priority, and
notifies the priority having been changed to the host computer.

2. The storage subsystem according to claim 1 , wherein
the respective owner is within the first subset, and
the new owner is selected from the second subset when the failure is detected in the respective owner and all other control packages in the first subset are in an error state.

3. The storage subsystem according to claim 1 ,
wherein
the respective owner is within the first subset, and
the new owner is selected from first subset when the failure is detected in the access path.

4. The storage subsystem according to claim 3 , wherein
the failure is detected in the access path when the plurality of control packages that are not the respective owner of the respective storage volume receive a number access requests for the respective storage volume exceed a given threshold value.

5. The storage subsystem according to claim 1 , wherein
the respective owner is within the first subset;
the storage subsystem determines the priority of the respective owner as the highest, the priority of other control packages in the first subset as a second highest, and the priority of the second subset as a third highest;
when the first subset can not receive the access request, the storage subsystem sets the second subset to receive the access request; and
the second subset transfers the access request via the second communication path to the respective owner.

6. The storage subsystem according to claim 1 , wherein
a part of an area of the memory in each of the plurality of control packages is configured as a cache area for caching data of the volume; and
when a write request to the volume is received from the host computer, a first control package being the owner of the volume stores a write data in the cache area within the first control package, and causes a second control package determined as a sub-owner having a role to store a replica of the write data to the volume to store the write data in the cache area within the second control package.

7. The storage subsystem according to claim 6 , wherein the respective owner is within the first subset,
and
when the second subset receives a given threshold or more of access requests the storage subsystem:
changes the respective owner to a control package within the second subset;
sets another control package as a sub-owner of the volume; and
destages a dirty data stored in the cache area within the control package within the first subset to the storage volume.

8. The storage subsystem according to claim 6 , wherein
the respective owner is within the first subset, and
the new owner is selected from the second subset when-multiple normal control packages do not exist in the first subset and
copies a dirty data stored in the cache area within the control package having been the sub-owner of the volume to the cache area within the control package set to become the owner of the volume.

9. The storage subsystem according to claim 6 , wherein:
the respective owner is within the first subset, and
when a given threshold value or more access requests from the host computer is received by the second subset, the storage subsystem:
changes the respective owner to a control package from the second subset;
sets another control package from within the first subset as a sub-owner of the volume; and
copies a clean data out of the data corresponding to the volume within the control package of the first subset to the cache area within the control package of the second subset.

10. A computer system comprising:
a host computer;
a storage subsystem having a plurality of control nodes for processing requests from the host computer, wherein the plurality of control nodes includes a first control node and a second control node;
a plurality of control packages each having a processor, a memory, and a port for receiving accesses from the host computer;
a first subset of the plurality of control packages that are mutually interconnected within the first control node via a respective first communication path;
a second subset of the plurality of control packages that are mutually interconnected within the second control node via a respective first communication path;
a second communication path that interconnects the first subset and the second subset the via a second communication path having a lower transmission path capacity than the first communication path; and
a plurality of owners that are each associated with a respective storage volume from a plurality of storage volumes, wherein each respective owner is a particular control package from the plurality of control packages that is configured to process an I/O request arriving from the host computer to the respective storage volume;
wherein the host computer accesses one or more of the plurality of storage volumes via any one of at least two or more of the plurality of control packages, and each of the plurality of control packages has a priority determined for issuing an access request from the host computer to the volume, and
wherein in response to detection of a failure in the storage subsystem, the storage subsystem:
selects a new owner of a particular volume according to a failure occurrence section, wherein a different owner is selected when the failure in the storage subsystem is detected in the respective owner then when the failure is detected an access path between the host computer and the respective owner,
raises the priority of the new owner to a highest priority, and
notifies the priority having been changed to the host

Assignees

• Hitachi Ltd

Inventors

• Kawaguchi Tomohiro
• Simozono Norio
• Saito Hideo
• Mizuno Makio

Classifications

• G06F3/0683

  Plurality of storage devices · CPC title

• G06F13/00

  Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units (interface circuits for specific input/output devices G06F3/00 {; multiprogram control therefor  G06F9/46}; multiprocessor systems  G06F15/16 ) · CPC title

• G06F11/2094 Primary

  Redundant storage or storage space (G06F11/2056 takes precedence) · CPC title

• G06F13/10

  Program control for peripheral devices (G06F13/14 - G06F13/42 take precedence) · CPC title

• G06F3/065

  Replication mechanisms · CPC title