Systems and methods for retaining and using data block signatures in data protection operations

• US 8,578,109 B2
• Filed: 12/30/2010
• Issued: 11/05/2013
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Vijayan, Manoj Kumar, Attarde, Deepak Raghunath
• Primary Examiner(s): KROFCHECK, MICHAEL C
• Application Number:
  US12/982,100
• Publication Number:
  US 20120084519A1
• Time in Patent Office: 1,041 Days
• Field of Search: None
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• 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 3/0683 Plurality of storage devices
• CPC Class Codes: H05K 999/99 dummy group

Abstract

A system according to certain embodiments associates a signature value corresponding to a data block with one or more data blocks and a reference to the data block to form a signature/data word corresponding to the data block. The system further logically organizes the signature/data words into a plurality of files each comprising at least one signature/data word such that the signature values are embedded in the respective file. The system according to certain embodiments reads a previously stored signature value corresponding to a respective data block for sending from a backup storage system having at least one memory device to a secondary storage system. Based on an indication as to whether the data block is already stored on the secondary storage system, the system reads the data block from the at least one memory device for sending to the secondary storage system if the data block exists on the secondary storage system, wherein the signature value and not the data block is read from the at least one memory device if the data block exists on the secondary storage system.

Claims

1. A method of performing a copy operation, the method comprising:

copying, with one or more processors comprising computer hardware, a plurality of files from primary storage to one or more first secondary storage devices, wherein the files are formed from a plurality of source data blocks, wherein said copying is performed in a deduplicated manner and at least partly by;

accessing a deduplication signature table containing a plurality of signatures which correspond to a plurality of backed up data blocks stored in the one or more first secondary storage devices; and

storing, on the one or more first secondary storage devices, instances of ones of the plurality of source data blocks for which matching backed up data blocks do not already exist on the one or more first secondary storage devices;

in response to instructions to copy at least some of the plurality of backed up data blocks from the one or more first secondary storage devices to one or more second secondary storage devices, for each respective data block of the at least some of the plurality of backed up data blocks;

reading, with one or more processors comprising computer hardware, a previously stored signature corresponding to the respective data block for sending from the one or more first secondary storage devices to the one or more second secondary storage devices, wherein the previously stored signature is stored on the one or more first secondary storage devices and is separate from the deduplication signature table; and

based on an indication as to whether the respective data block is already stored on the one or more second secondary storage devices, reading the respective data block from the one or more first secondary storage devices for sending to the one or more second secondary storage devices if the respective data block does not exist on the one or more second secondary storage devices, wherein the signature corresponding to the respective data block and not the respective data block itself is read from the one or more first secondary storage devices if the respective data block exists on the one or more second secondary storage devices.

2. The method of claim 1, further comprising, for each respective data block of the plurality of the backed up data blocks:

associating the signature corresponding to the respective data block with one or more of the respective data block or a reference to the respective data block to form a signature/data word; and

storing the signature/data word on the one or more first secondary storage devices.

3. The method of claim 2, further comprising logically organizing the signature/data words into files each including one or more signature/data words such that the signatures are embedded in the files.

4. The method of claim 1, wherein the deduplication signature table resides in a backup storage system which includes the one or more first secondary storage devices.

5. The method of claim 4, wherein the backup storage system generates the signatures in response to receiving the corresponding source data blocks, and wherein the backup storage system completes the copy of the at least some of the plurality of backed up data blocks from the one or more first secondary storage devices to the one or more second secondary storage devices without re-generating the signature values.

6. The method of claim 4, wherein the backup storage system stores deduplicated data.

7. The method of claim 1, wherein the data block size is at least 512 times larger than the signature size.

8. The method of claim 1, wherein the plurality of source data blocks and corresponding signatures are received from a client system, and wherein the copy of the at least some of the plurality of backed up data blocks from the one or more first secondary storage devices to the one or more second secondary storage devices is completed without generating the signature values.

9. The method of claim 1, wherein the one or more second secondary storage devices store deduplicated data.

10. A system for performing a copy operation, the system comprising:

one or more processors comprising computer hardware;

at least one copy management module executing in the one or more processors and configured to;

copy a plurality of files from primary storage to one or more first secondary storage devices, wherein the files are formed from a plurality of source data blocks, wherein said copying is performed in a deduplicated manner and at least partly by;

accessing a deduplication signature table containing a plurality of signatures which correspond to a plurality of backed up data blocks stored in the one or more first secondary storage devices; and

storing, on the one or more first secondary storage devices, instances of ones of the plurality of source data blocks for which matching backed up data blocks do not already exist on the one or more first secondary storage devices; and

in response to instructions to copy at least some of a plurality of backed up data blocks stored in the one or more first secondary storage devices to one or more second secondary storage devices, for each respective data block of the at least some of the plurality of backed up data blocks;

read a previously stored signature corresponding to the respective data block for sending from the one or more first secondary storage devices to the one or more second secondary storage devices, wherein the previously stored signature is stored on the one or more first secondary storage devices and is separate from the deduplication signature table; and

based on an indication as to whether the respective data block is already stored on the one or more second secondary storage devices, read the respective data block from the one or more first secondary storage devices for sending to the one or more second secondary storage devices if the respective data block does not exist on the one or more second secondary storage devices, wherein the signature corresponding to the respective data block and not the respective data block itself is read from the one or more first secondary storage devices if the respective data block exists on the one or more second secondary storage devices.

11. The system of claim 10, further comprising a data packaging module executing in the one or more processors and configured to, for each respective data block of the plurality of backed up data blocks:

associate the signature corresponding to the respective data block with one or more of the respective data block or a reference to the data block to form a signature/data word; and

store the signature/data word on the one or more first secondary storage devices.

12. The system of claim 11, wherein the data packaging module logically organizes the signature/data words into files each including one or more signature/data words such that the signatures are embedded in the files.

13. The system of claim 10, wherein the data block size is at least 512 times larger than the signature size.

14. The system of claim 10, wherein the system further comprises a signature generation module configured to generate the signature in response to receiving the corresponding source data blocks, and wherein the copy management module is configured to complete the copy of the at least some of the plurality of backed up data blocks from the one or more first secondary storage devices to the one or more second secondary storage devices without re-generating the signature values.

15. The method of claim 10, wherein the plurality of source data blocks and corresponding signatures are received from a client system, and wherein the copy management module is configured to complete the copy of the at least some of the plurality of backed up data blocks from the one or more first secondary storage devices to the one or more second secondary storage devices without generating the signature values.