Concurrency control in a file system shared by application hosts

• US 8,521,686 B2
• Filed: 07/13/2009
• Issued: 08/27/2013
• Est. Priority Date: 07/13/2009
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: Rajagopal, Haripriya, Vaghani, Satyam, Tan, Yuen-Lin
• Primary Examiner(s): Pham, Hung Q
• Assistant Examiner(s): CHEUNG, HUBERT G
• Application Number:
  US12/502,086
• Publication Number:
  US 20110010390A1
• Time in Patent Office: 1,506 Days
• Field of Search: 707/613
• US Class Current: 707/613
• CPC Class Codes: G06F 16/1767 Concurrency control, e.g. optimistic or pessimistic approaches
• 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

A manager program for managing virtual machines includes a process which receives a notification message indicating an occurrence of an event affecting a data storage unit in a data storage system that supports a shared file system. The notification message might have come from a virtual machine host or resulted from a hardware reconfiguration. The manager program then determines whether another virtual machine host is sharing the data storage unit. The manager program might make this determination by polling each of the virtual machine hosts it manages or by checking information previously collected and stored in a database. If another virtual machine host is sharing the data storage unit, the manager program sends a refresh message to that virtual machine host that causes the virtual machine host to update information relating to the data storage unit in a cache associated with the virtual machine host.

Claims

1. A method, comprising:

sharing a plurality of logical units in a data storage system among a plurality of hosts, wherein the plurality of logical units are available to be formatted with a file system associated with any of the plurality of hosts to form a logical data storage entity for one of the plurality of hosts, the logical data storage entity including a set of logical units from the plurality of logical units that have been formatted with the file system;

receiving a notification message from a first host indicating an occurrence of an event corresponding to a logical unit of the data storage system, wherein the event relates to use of the logical unit in relation to a logical data storage entity associated with the first host that is identified by a data storage entity identifier and associated with a file system, wherein the logical unit is part of the logical data storage entity and is associated with the file system of the logical data storage entity;

determining whether a second host having access to the data storage system also shares access to the logical unit with the first host; and

sending, by a computing device, a refresh message to the second host that causes the second host to update information relating to the logical data storage entity associated with the first host that includes the logical unit in a cache of the second host to reflect the occurrence of the event, wherein the data storage entity identifier associated with the data storage entity is identified as including the logical unit in the cache to indicate the logical unit is formatted by the file system of the logical data storage entity thereby preventing the second host from performing a second event corresponding to the logical unit that is inconsistent with the event.

2. The method as in claim 1, wherein the received notification message indicates that the first host performed an operation on the logical unit that resulted in the logical unit being formatted by the file system.

3. The method as in claim 1, wherein the event is in response to at least one of creating the file system, upgrading the file system, growing the file system, spanning the logical unit that was previously unused, and removing the logical unit.

4. The method as in claim 1, wherein the event is a hardware reconfiguration such as an addition, a removal or a failure related to the logical unit.

5. The method as in claim 1, wherein the refresh message causes the second host to update information relating to only the logical unit.

6. The method as in claim 1, wherein the determining whether the second host also shares the logical unit includes sending a polling message querying the second host as to whether the second host is sharing the logical unit and receiving a response message from the second host indicating that the second host is sharing the logical unit.

7. The method as in claim 6, wherein the received response message is stored in a database for subsequent access.

8. The method as is claim 1, further comprising an operation of displaying one or more views in a graphical user interface that includes the updated information relating to the logical unit.

9. The method as in claim 1, wherein:

the update of the information comprises indicating the logical unit is formatted with the file system of the first host in the cache of the second host; and

the updated information indicates a file system of the second host should not be applied to the logical unit.

10. The method as in claim 9, wherein the file system of the second host is a different file system format from the file system of the first host.

11. The method as in claim 1, wherein a second file system of the second host shares a same format as the file system of the first host.

12. A non-transitory computer-readable storage medium containing instructions for controlling a computer system configured to:

share a plurality of logical units in a data storage system among a plurality of hosts, wherein the plurality of logical units are available to be formatted with a file system associated with any of the plurality of hosts to form a logical data storage entity for one of the plurality of hosts, the logical data storage entity including a set of logical units from the plurality of logical units that have been formatted with the file system;

receiving a notification message from a first host indicating an occurrence of an event corresponding to a logical unit of the data storage system, wherein the event relates to use of the logical unit in relation to a logical data storage entity associated with the first host that is identified by a data storage entity identifier and associated with a file system, wherein the logical unit is part of the logical data storage entity and is associated with the file system of the logical data storage entity;

determining whether a second host having access to the data storage system also shares access to the logical unit with the first host; and

send a refresh message to the second host that causes the second host to update information relating to the logical data storage entity associated with the first host that includes the logical unit in a cache of the second host to reflect the occurrence of the event, wherein the data storage entity identifier associated with the data storage entity is identified as including the logical unit in the cache to indicate the logical unit is formatted by the file system of the logical data storage entity thereby preventing the second host from performing a second event corresponding to the logical unit that is inconsistent with the event.

13. The non-transitory computer-readable storage medium in claim 12, wherein the received notification message is from the first host which shares the logical unit and wherein the received notification message indicates that the first host performed an operation on the logical unit that resulted in the logical unit being formatted by the file system.

14. The non-transitory computer-readable storage medium in claim 13, wherein the event is in response to at least one of creating the file system, upgrading the file system, growing the file system, and spanning the logical unit that was previously unused.

15. The non-transitory computer-readable storage medium in claim 12, wherein the event is a hardware failure related to the logical unit.

16. The non-transitory computer-readable storage medium in claim 12, wherein the refresh message causes the second host to update information relating to only the logical unit.

17. The non-transitory computer-readable storage medium in claim 12, wherein the determination as to whether the second host also shares the logical unit includes sending a polling message querying the second host as to whether the second host is sharing the logical unit and receiving a response message from the second host indicating that the second host is sharing the logical unit.

18. The non-transitory computer-readable storage medium in claim 17, wherein the received response message is stored in a database for subsequent access.

19. A method, comprising:

sharing a plurality of logical units in a data storage system among a plurality of hosts, wherein the plurality of logical units are available to be formatted with a file system associated with any of the plurality of hosts to form a logical data storage entity for one of the plurality of hosts, the logical data storage entity including a set of logical units from the plurality of logical units that have been formatted with the file system;

receiving a notification message from a first host indicating an occurrence of an event corresponding to a logical unit of the data storage system, wherein the event relates to use of the logical unit in relation to a logical data storage entity associated with the first host that is identified by a data storage entity identifier and associated with a file system, wherein the logical unit is part of the logical data storage entity and is associated with the file system of the logical data storage entity;

determining whether an application program having access to the data storage system also shares access to the logical unit with the first host; and

sending, by a computing device, a refresh message to the application program that causes the application program to update information relating to the logical data storage entity associated with the first host that includes the logical unit in a cache of the application program to reflect the occurrence of the event, wherein the data storage entity identifier associated with the data storage entity is identified as including the logical unit in the cache to indicate the logical unit is formatted by the file system of the logical data storage entity thereby preventing the application program from performing a second event corresponding to the logical unit that is inconsistent with the event.

20. The method as in claim 19, wherein the received notification message is from another application program of the first host which shares the logical unit and wherein the received notification message indicates that the another application program performed an operation on the logical unit that resulted in the logical unit being formatted by the file system.

21. The method as in claim 19, wherein the event is a hardware failure related to the logical unit.