DATA BLOCK MIGRATION

• US 20120084527A1
• Filed: 06/10/2011
• Published: 04/05/2012
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Quest Software, Inc.
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Jayaraman, Vinod, Dinkar, Abhijit, Taylor, Mark, Rao, Goutham, Root, Michael E., Bashyam, Murali
• Granted Patent: US 9,400,799 B2
• Time in Patent Office: Days
• US Class Current: 711/165
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0667 at data level, e.g. file, record or object virtualisation
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Techniques and mechanisms are provided for migrating data blocks around a cluster during node addition and node deletion. Migration requires no downtime, as a newly added node is immediately operational while the data blocks are being moved. Blockmap files and deduplication dictionaries need not be updated.

Claims

1. A method, comprising:

receiving a request to add a new node from a data storage cluster;

generating a plurality of new keys associated with a mapping function, the mapping function identifying a particular node corresponding to a particular key;

copying data from the plurality of existing nodes to the new node to rebalance data across the data storage cluster.

2. The method of claim 1, wherein each of the plurality of new keys includes a node number.

3. The method of claim 1, wherein the plurality of new keys correspond to a plurality of blockmap files.

4. The method of claim 3, wherein each blockmap file includes offset, length, and location identifiers for identifying segments in a plurality of suitcases.

5. The method of claim 3, wherein the plurality of blockmap files remain unchanged after adding the new node.

6. The method of claim 1, wherein the plurality of new keys are a plurality of suitcase identifiers (scids).

7. The method of claim 6, wherein the mapping function comprises the following:

#define get_the_node_number_from_the_scid(_scid_) scid_to_node_array[_scid_% MAX_CLUSTER_SIZE]

8. The method of claim 1, wherein the new node is a storage device.

9. The method of claim 1, wherein the new node is a storage array.

10. The method of claim 1, wherein a plurality of segments are copied onto a suitcase maintained at the new node.

11. The method of claim 1, wherein the mapping function can be changed while the plurality of new keys are being generated.

12. A system, comprising:

an interface configured to receive a request to add a new node from a data storage cluster;

a processor configured to generate a plurality of new keys associated with a mapping function, the mapping function identifying a particular node corresponding to a particular key, the processor further configured to copy data from the plurality of existing nodes to the new node to rebalance data across the data storage cluster.

13. The system of claim 12, wherein each of the plurality of new keys includes a node number.

14. The system of claim 12, wherein the plurality of new keys correspond to a plurality of blockmap files.

15. The system of claim 14, wherein each blockmap file includes offset, length, and location identifiers for identifying segments in a plurality of suitcases.

16. The system of claim 14, wherein the plurality of blockmap files remain unchanged after adding the new node.

17. The system of claim 12, wherein the plurality of new keys are a plurality of suitcase identifiers (scids).

18. A method, comprising:

receiving a request to add a new node from a data storage cluster;

generating a plurality of new keys associated with a mapping function, the mapping function identifying a particular node corresponding to a particular key;

copying data from the plurality of existing nodes to the new node to rebalance data across the data storage cluster.

19. The method of claim 18, wherein each of the plurality of new keys includes a node number.

20. The method of claim 18, wherein the plurality of new keys correspond to a plurality of blockmap files.