Storage array side write locking

• US 9,560,134 B1
• Filed: 06/27/2012
• Issued: 01/31/2017
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Smith, Hubbert
• Primary Examiner(s): Alam, Uzma
• Application Number:
  US13/534,923
• Time in Patent Office: 1,679 Days
• Field of Search: 709/223, 714/218, 714/42
• US Class Current: 1/1
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

Systems and methods are described herein that provide storage array side write locking. In embodiments, data is on storage arrays that are shared by a plurality of clients, and the storage array prevents write contentions on the shared data by employing a storage array side write locking strategy that uses a write lock table to determine whether requested data is currently being serviced by one of the plurality of clients. For example, upon receiving a request for data, the storage array checks a lock table to determine whether any of the requested data is currently write locked (which indications current use of the data). If the grains are not write locked, then the data request may be allowed. If the grains are write locked, then the data request may be denied. In embodiments, the storage array takes steps to determine whether write locks have become stale and should be removed.

Claims

1. A method comprising:

receiving, at one of a plurality of storage arrays, a request to access grains stored in one or more of the plurality of storage arrays from one of a plurality of clients;

determining, by the one of the plurality of storage arrays, from a lock table a lock status of each of the requested grains and an identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

managing, by the one of the plurality of storage arrays, access to each of the requested grains based on the determined lock status and the identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

locking, by the one of the plurality of storage arrays, in the lock table the grains to the client associated with the request when the determining indicates the lock status is unlocked; and

waiting a stored period of time and then repeating the determining and the managing for a stored number of attempts for grains which remain when the determining indicates the lock status is locked.

2. The method of claim 1 further comprising:

changing, by the one of the plurality of storage arrays the lock status of at least one of the grains from locked to unlocked based upon an event.

3. The method of claim 2 wherein the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has completed operations on the at least one of the grains.

4. The method of claim 2 wherein the event is based on a time stamp.

5. The method of claim 2 where the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has become noncommunicative.

6. A storage array device in a cluster of storage array devices, the storage array device comprising:

one or more processors;

a memory device coupled to the one or more processors which are configured to be capable of executing programmed instructions comprising and stored in the memory device to;

receive a request to access grains stored in one or more of the cluster of storage array devices from one of a plurality of clients;

determine from a lock table a lock status of each of the requested grains and an identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

manage access to each of the requested grains based on the determined lock status and the identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

lock in a lock table the grains to the client associated with the request when the determine indicates the lock status is unlocked; and

wait a stored period of time and then repeating the determine the lock status and the manage access for a stored number of attempts for the grains which remain when the determine the lock status indicates the lock status is locked.

7. The device of claim 6 wherein the memory coupled to the one or more processors is further configured to be capable of executing programmed instructions comprising and stored in the memory to change the lock status of at least one of the grains from locked to unlocked based upon an event.

8. The device of claim 7 wherein the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has completed operations on the at least one of the grains.

9. The device of claim 7 wherein the event is based on a time stamp.

10. The device of claim 7 wherein the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has become noncommunicative.

11. A non-transitory, machine readable storage medium having stored thereon instructions for performing a method, comprising machine executable code which when executed by at least one machine, causes the machine to:

receive, at one of a plurality of storage arrays, a request to access grains stored in one or more of the plurality of storage arrays from one of a plurality of clients;

determine, by the one of the plurality of storage arrays, from a lock table a lock status of each of the requested grains and an identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

manage, by the one of the plurality of storage arrays, access to each of the requested grains based on the determined lock status and the identification of which of the plurality of clients is associated with each of the requested grains with the lock status of locked;

lock, by the one of the plurality of storage arrays, in the lock table the grains to the client associated with the request when the determining indicates the lock status is unlocked; and

wait a stored period of time and then repeating the determining and the managing for a stored number of attempts for grains which remain when the determining indicates the lock status is locked.

12. The non-transitory storage medium of claim 11 wherein the machine executable code further causes the machine to:

change, by the one of the plurality of storage arrays the lock status of at least one of the grains from locked to unlocked based upon an event.

13. The non-transitory storage medium of claim 12 wherein the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has completed operations on the at least one of the grains.

14. The non-transitory storage medium of claim 12 wherein the event is based on a time stamp.

15. The non-transitory storage medium of claim 12 where the event is a determination that the one of the plurality of clients associated with the at least one of the grains with the lock status of locked has become noncommunicative.