COPY ON WRITE STORAGE CONSERVATION SYSTEMS AND METHODS

• US 20110219201A1
• Filed: 03/02/2010
• Published: 09/08/2011
• Est. Priority Date: 03/02/2010
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Ranade, Dilip Madhusudan
• Granted Patent: US 9,015,430 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/1727 Details of free space management performed by the file system saving storage space on storage systems G06F3/0608; management of blocks in storage devices G06F3/064
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

Systems and methods for copy on write storage conservation are presented. In one embodiment a copy on write storage conservation method includes creating and mounting a snapshot; mounting a snapshot; monitoring interest in the snapshot; initiating a copy on write discard process before a backup or replication is complete; and deleting the snapshot when the backup or replication is complete. In one embodiment the method also includes marking a file as do not copy on write. In one embodiment, the copy on write discard process includes discarding copy on write data when a corresponding read on the file in the snapshot is successful. Initiating a copy on write discard process can be done at a variety of levels (e.g., a file level, an extent level, a block-level, etc.).

Claims

1. A copy on write storage conservation method comprising:

creating and mounting a snapshot;

monitoring interest in the snapshot;

initiating a copy on write discard process before a backup or replication is complete; and

un-mounting and deleting the snapshot when the backup or replication is complete.

2. The method of claim 1 further comprising marking a file as do not copy on write.

3. The method of claim 1 wherein the copy on write discard process includes discarding copy on write data when a corresponding read on a block is successful.

4. The method of claim 1 wherein the copy on write discard process includes a signal to delete copy on write blocks and the signal is associated with a close( ) function of a file indicating reads of information from the file are finished.

5. The method of claim 1 wherein the copy on write discard process includes:

determining backup or replication applications read file data in peculiar patterns; and

deleting copy on write data for a particular file when it is safe in accordance with the peculiar pattern.

6. The method of claim 1 wherein the initiating a copy on write discard process is done at a file level, block level and extent level.

7. The method of claim 1 wherein a public application program interface is available to set the snapshot in an aggressive de-allocation mode initiated before the completion of the backup or replication.

8. A computer readable storage medium having stored thereon, computer-executable instructions that when executed by a computing device cause the computing device to perform a copy on write storage conservation method comprising:

creating and mounting a snapshot;

monitoring interest in the snapshot;

initiating a copy on write discard process before a backup or replication is complete; and

un-mounting and deleting the snapshot when the backup or replication is complete.

9. The computer readable storage medium of claim 8 further comprising marking a file as do not copy on write.

10. The computer readable storage medium of claim 8 wherein the copy on write discard process includes discarding copy on write data when a corresponding read on a block is successful.

11. The computer readable storage medium of claim 8 wherein the copy on write discard process includes a signal to delete copy on write blocks and the signal is associated with a close( ) function of the file indicating reads of information from the file are finished.

12. The computer readable storage medium of claim 8 wherein the copy on write discard process includes:

determining backup or replication applications read file data in peculiar patterns; and

discarding the copy on write data for a particular file when it is safe in accordance with the peculiar pattern.

13. The computer readable storage medium of claim 8 wherein the initiating a copy on write discard process is done at a file level, block level and extent level.

14. The computer readable storage medium of claim 8 wherein a public application program interface is available to set the snapshot in an aggressive de-allocation mode initiated before the completion of the backup or replication.

15. A system, comprising:

a computer system having a processor coupled to a computer readable storage media and executing computer readable code which causes the computer system to perform a copy on write storage conservation method comprising;

creating and mounting a snapshot;

monitoring interest in the snapshot;

initiating a copy on write discard process before a backup or replication is complete; and

un-mounting and deleting the snapshot when the backup or replication is complete.

16. The system of claim 15 further comprising marking a file as do not copy on write.

17. The system of claim 15 wherein the copy on write discard process includes discarding copy on write data when a corresponding read on a block is successful.

18. The system of claim 15 wherein the copy on write discard process includes a signal to delete copy on write blocks and the signal is associated with a close( ) function of the file indicating reads of information from the file are finished.

19. The system of claim 15 wherein the copy on write discard process includes:

determining backup or replication applications read file data in peculiar patterns; and

discarding the copy on write data for a particular file when it is safe in accordance with the peculiar pattern.

20. The system of claim 15 wherein the initiating a copy on write discard process is done in at a file level, block level and extent level.