System and method for addressing data containers using data set identifiers

• US 8,489,811 B1
• Filed: 12/29/2006
• Issued: 07/16/2013
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Corbett, Peter F., Jernigan, Richard P. IV, Ramani, Balaji, Simharajan, Srishylam, Eisler, Michael, Kazar, Michael, Vully, Vani
• Primary Examiner(s): Peugh, Brian
• Assistant Examiner(s): Cygiel, Gary W
• Application Number:
  US11/648,161
• Time in Patent Office: 2,391 Days
• Field of Search: None
• US Class Current: 711/114
• CPC Class Codes: G06F 16/188 Virtual file systems

Abstract

A system and method addresses data containers in a clustered storage system. Each instantiation of a volume, or other container set, is associated with a data set identifier (DSID). All instantiations of data that represent a single point in time are associated with a master data set identifier (MSID). A volume location database (VLDB), utilizing a replicated database among the nodes of the cluster, stores a data set data structure containing appropriate mapping information between the MSIDs and DSIDs. Clients of the clustered storage system utilize MSIDs to reference data that is desired to be accessed. When a storage system receives a data access request containing a MSID, the storage system accesses the VLDB to identify an appropriate DSID to which to forward the request. The data access request is then forwarded to the appropriate storage system for processing.

Claims

1. A method for processing a plurality of data access requests addressing a data container in a clustered storage system, the clustered storage system including a plurality of nodes configured to receive the plurality of data access requests, the method comprising:

associating a first data set identifier with the data container, the data container generated and stored on a first node of the clustered storage system;

creating a master data set identifier at the first node of the clustered storage system;

associating a second data set identifier with an instantiation of the data container that represents a single point in time image of the data container, wherein the first data set identifier is different than the second data set identifier, wherein the instantiation of the data container is stored on a second node of the clustered storage system, and wherein the first data container and second data container have distinct inode address spaces;

associating the master data set identifier with the first data set identifier and the second data set identifier;

receiving, at a third node of the clustered storage system, a first data access request of the plurality of data access requests directed to the master data set identifier using a network protocol;

forwarding the first data access request to the first node to service the first data access request from the data container, wherein the forwarded first data access request includes an inode number;

replying to the first data access request upon service completion of the first data access request, wherein the reply to the first data access request includes the master data set identifier;

receiving, at the third node of the clustered storage system, a second data access request of the plurality of data access requests directed to the master data set identifier using the network protocol;

forwarding the second data access request to the second node to service the second data access request from the instantiation of the data container, wherein the forwarded second data access request includes the inode number and the master data set identifier; and

replying to the second data access request upon service completion of the second data access request, wherein the reply to the second data access request includes the master data set identifier.

2. The method of claim 1 wherein each data access request comprises a file handle, and wherein the generated value of the master data set identifier is at least 32 bits in length.

3. The method of claim 1 wherein the instantiation of the data container is associated with a name, and wherein the first and second data set identifiers are numeric values.

4. The method of claim 1 further comprising:

identifying the first node as storing the data container using a database that includes a plurality of entries, wherein an entry associates the first data set identifier with the master data set identifier and with the first node.

5. The method of claim 4 further comprising identifying the clustered storage system associated with the first data set identifier within the entry of the plurality of entries of the database.

6. The method of claim 1 further comprising:

in response to a failure of the first data access request, identifying the second data set identifier associated with the master data set identifier; and

forwarding the first data access request to the second node to service the first data access request from the instantiation of the data container.

7. The method of claim 1 wherein the instantiation of the data container is a mirror of the data container.

8. The method of claim 1 wherein the network protocol is a Network File System protocol.

9. The method of claim 1 wherein the first data access request comprises a first file handle and the second data access request comprises a second file handle, and wherein the first and second file handles include the master data set identifier.

10. The method of claim 1, wherein the first data set identifier identifies a first file system and the second data set identifier identifies a second file system.

11. The method of claim 1, wherein the master data set identifier identifies a source volume.

12. The method of claim 1, wherein the first identifier identifies a volume and the second identifier identifies a second volume.

13. A system configured to address a data container in a clustered storage system, the system comprising:

means for associating a first data set identifier with the data container and a different data set identifier with each instantiation of the data container that represents a single point in time image of the data container;

means for associating a master data set identifier with the first data set identifier and the different data set identifier associated with each instantiation of the data container, wherein the master data set identifier is a created value within the clustered storage system, wherein each data set identifier is a generated value having a same bit-length as the master data set identifier, and wherein each instantiation of the data container has a distinct inode address space;

means for receiving at a network element on a storage system of the clustered storage system, a data access request directed to the master data set identifier using a Network File System protocol;

means for identifying at the network element one of the data set identifiers associated with the master data set identifier, by reading an associated data set identifier data structure that includes a master data set identifier field and one or more data set identifier fields to enable mapping between the master data set identifier and the one or more data set identifiers to forward the data access request thereto,

means for mapping the master data set identifier to one of the data set identifiers;

means for identifying one of the data set identifiers to satisfy the data access request; and

means for forwarding, from the storage system that received the data access request, the identified data set identifier associated with the master data set identifier, wherein the means for forwarding includes an inode number and the master data set identifier;

means for replying to the data access request, wherein the reply to the data access request includes the master data set identifier.

14. A system configured to receive a data access request addressing one or more data containers in a storage system cluster, the clustered storage system including a plurality of nodes configured to receive the data access request, the system comprising:

a plurality of disk elements serviced by the storage system cluster, each data container having one or more instantiations served by one or more differing disk elements of the cluster;

a volume location database storing a data set identifier data structure associating a master data set identifier created within the clustered storage system with one or more data set identifiers, each of the data set identifiers associated with a different instantiation of same data stored in the one or more data containers, wherein each of the one or more data containers has a distinct inode address space; and

a network element of the cluster configured to receive a data access request having a data container handle containing the master data set identifier, wherein the network element is further configured to access the volume location database to identify one of the data set identifiers associated with the master data set identifier and forward the data access request to one of the disk elements serving the different instantiation associated with the identified data set identifier, wherein the master data set identifier is a generated value, wherein each data set identifier is a generated value having a same bit-length as the master data set identifier, wherein the forwarded data access request includes an inode number and the master data set identifier, and wherein the reply to the data access request includes the master data set identifier.

15. The system of claim 14 wherein the network element is further configured to, in response to an error condition, identify a another data set identifier associated with the master data set identifier.

16. The system of claim 15 wherein the network element is further configured to forward the data access request to one of the disk elements serving the different instantiation associated with the another data set identifier.

17. The system of claim 14 wherein the data set identifier data structure comprises one or more entries associated with the one or more instantiations of the data container.

18. The system of claim 14 wherein the data set identifier data structure identifies which of the disk elements to serve each of the one or more instantiations of the data container.

19. The system of claim 14 wherein one of the one or more instantiations of the data container comprises a persistent consistency point image.

20. The system of claim 14 wherein one of the one or more instantiations of the data container comprises a minor.

21. The method of claim 14 wherein the data access is a Network File System protocol read request.