Consistency group management

• US 9,952,767 B2
• Filed: 04/29/2016
• Issued: 04/24/2018
• Est. Priority Date: 04/29/2016
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Zheng, Ling, Zhao, Ning, Aster, Radek, Kimmel, Jeffrey S.
• Primary Examiner(s): Portka, Gary J
• Application Number:
  US15/142,767
• Publication Number:
  US 20170315728A1
• Time in Patent Office: 725 Days
• Field of Search: 711154, 711162, 711170, 711203
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A consistency group is used as a basic unit of data management of storage containers served by a storage input/output (I/O) stack executing on one or more nodes of a cluster. The storage container may be a LUN embodied as parent volume (active volume), a snapshot (represented as an independent volume embodied as read-only copy of the active volume), and a clone (represented as another independent volume embodied as a read-write copy (clone) of the active volume). A consistency group (CG) is a set (i.e., collection) of objects, e.g., LUNs or other CGs (nested CG), which may be managed and operated upon collectively by an administrative command via a Storage Area Network administration layer (SAL) of the storage I/O stack. The SAL may interact with one or more layers of the storage I/O stack to (i) create a clone of a set of object members of the CG; (ii) create one or more snapshots of the set of object members of the CG; (iii) restore the set of object members of the CG from a group of CG snapshots; (iv) replicate the set of object members of the CG as a single entity; and (v) delete a CG and a nested CG according to specific semantics.

Claims

1. A method comprising:

receiving an administrative command directed to a first set of storage containers to create a first consistency group served by a storage system having a storage array of storage devices configured to store the storage containers;

processing the administrative command for each member of the first set of storage containers to create the first consistency group having a second set of storage containers, wherein each member of the second set of storage containers is created as a result of the processing of the administrative command on a corresponding member of the first set of storage containers, wherein each member of the first set of storage containers is a first child object of the first consistency group in a hierarchical namespace of the storage system;

determining whether the processing of the administrative command for a member of the first set of storage containers completes unsuccessfully; and

in response to determining that the processing of the administrative command for the member of the first set of storage containers completes unsuccessfully, deleting all members of the second set of storage containers and returning an unsuccessful completion to the received administrative command to create the first consistency group.

2. The method of claim 1 wherein the administrative command is selected from a group consisting of a command to create a snapshot of a storage container and a command to create a clone of the storage container.

3. The method of claim 2 wherein the first set of storage containers includes logical units.

4. The method of claim 2 wherein the first set of storage containers includes a second consistency group having a third set of storage containers.

5. The method of claim 1 wherein each member of the second set of storage containers is associated with a universally unique identifier stored in a database of the storage system.

6. The method of claim 4 wherein the second consistency group is a second child object of the first consistency group in the hierarchical namespace of the storage system, and wherein the second consistency group is destroyable without deleting the third set of storage containers.

7. The method of claim 1 wherein a pathname in the hierarchical namespace for each first child object of the first consistency group is unique within the namespace.

8. The method of claim 6 further comprising:

destroying the second consistency group such that the first consistency group becomes a parent of the third set of storage containers.

9. The method of claim 1 wherein a first member and a second member of the second set of storage containers are snapshots having a different creation time from the first consistency group.

10. A system comprising

a storage system connected to a processor;

and

a storage I/O stack executing on the processor of the storage system, the storage I/O stack configured to;

receive an administrative command directed to a first set of storage containers to create a first consistency group served by the storage system;

process the administrative command for each member of the first set of storage containers to create the first consistency group having a second set of storage containers, wherein each member of the second set of storage containers is created as a result of the processing of the administrative command on a corresponding member of the first set of storage containers, wherein each member of the first set of storage containers is a first child object of the first consistency group in a hierarchical namespace of the storage system;

determine whether the processing of the administrative command for a member of the first set of storage containers completes unsuccessfully; and

in response to determining that the processing of the administrative command for the member of the first set of storage containers completes unsuccessfully, delete all members of the second set of storage containers and return an unsuccessful completion to the received administrative command to create the first consistency group.

11. The system of claim 10 wherein the administrative command is selected from a group consisting of a command to create a snapshot of a storage container and a command to create a clone of the storage container.

12. The system of claim 11 wherein the first set of storage containers include logical units.

13. The system of claim 11 wherein the first set of storage containers includes a second consistency group having a third set of storage containers.

14. The system of claim 10 wherein each member of the second set of storage containers is associated with a universally unique identifier stored in a database of the storage system.

15. The system of claim 13 wherein the second consistency group is a second child object of the first consistency group in the hierarchical namespace of the storage system, and wherein the second consistency group is destroyable without deleting the third set of storage containers.

16. The system of claim 10 wherein a pathname in the hierarchical namespace for each first child object of the first consistency group is unique within the namespace.

17. The system of claim 15 wherein the storage I/O is stack further configured to:

destroy the second consistency group such that the first consistency group becomes a parent of the third set of storage containers.

18. A non-transitory computer readable medium including program instructions for execution on a processor of a storage system, the processor executing a storage input/output (I/O) stack, the program instructions configured to:

receive an administrative command directed to a first set of storage containers to create a first consistency group;

process the administrative command for each member of the first set of storage containers to create the first consistency group having a second set of storage containers, wherein each member of the second set of storage container is created as a result of the processing of the administrative command on a corresponding member of the first set of storage containers, wherein each member of the first set of storage containers is a child object of the first consistency group in a hierarchical namespace of the storage system;

determine whether the processing of the administrative command for a member of the first set of storage containers completes unsuccessfully; and

in response to determining that the processing of the administrative command for the member of the first set of storage containers completes unsuccessfully, delete all members of the second set of storage containers and return an unsuccessful completion to the received administrative command to create the first consistency group.