Incremental backup with eventual name space consistency
Systems and methods for backing up data are disclosed. Changes made to a file system are tracked in a change log. When a backup operation is initiated, the changes identified in the change log are applied to the backup save sets. When a file associated with an event in the change log cannot be identified, the file is identified using the inode or other identifier. The event in the change log is then applied once the file is identified. The backup so achieved has eventual name space consistency and can be achieved without taking a snapshot of the file system.
1. A method for performing a backup operation in a live file system, the method comprising:
during operation of the live file system:
closing a current change log when the backup operation is initiated such that the current change log is associated with the backup operation and starting a new change log for a subsequent backup operation, wherein the current change log includes records of operations that were performed in the live file system and identifies blocks of the data or files that have changed since a previous backup operation, wherein the current change log is configured to store an inode number for each of the data or files that have changed;
backing up, by the backup server, the blocks of data or files identified in the current change log on a backup storage device from the live file system in a backup save set;
identifying a name and/or path of the data blocks or files that cannot be read by the backup application in the live file system because of the changes that continue to occur in the live file system; and
determining a current name and/or path of the files or data blocks that could not be read by the backup application from the new change log using the inode numbers stored in the current change log; and
changing the backup save set such that the backup save set is namespace consistent with the data blocks or files based on the current name and/or path of the data blocks.
2. The method of claim 1 , further comprising initiating the backup operation of the live file system.
3. The method of claim 2 , further comprising performing the backup operation while the live file system continues operation.
4. The method of claim 1 , further comprising storing the current change log with the backup save set.
5. The method of claim 1 , further comprising accessing the files that cannot be read based on the inode numbers associated with the files that cannot be read, wherein the inode numbers enable the backup application to determine a current path and name of the files that cannot be initially read such that the backup applicant can make the backup save set name space consistent with the live file system.
6. The method of claim 5 , further comprising opening the files and passing a reference to the newly opened files to the backup application.
7. The method of claim 5 , further comprising performing events that correspond to the newly opened files.
8. The method of claim 7 , further comprising deleting any reference to a file when a reference to the file returned to the backup application is NULL.
9. The method of claim 1 , wherein modifications to the files are stored in the change log.
10. The method of claim 2 , further comprising initiating the backup operation of the live file system without taking a snapshot of the live file system.
11. The method of claim 1 , further comprising ensuring that changes to the files that cannot be initially read are included in the backup save set of the live file system.
12. A non-transitory computer readable medium comprising computer executable instructions that are configured to perform a method for performing a backup operation in a live file system, the method comprising:
during operation of the live file system:
closing a current change log when the backup operation is initiated such that the current change log is associated with the backup operation and starting a new change log for a subsequent backup operation, wherein the current change log includes records of operations that were performed in the live file system and identifies blocks of the data or files that have changed since a previous backup operation, wherein the current change log is configured to store an inode number for each of the data or files that have changed;
backing up, by the backup server, the blocks of data or files identified in the current change log on a backup storage device from the live file system in a backup save set;
identifying a name and/or path of the data blocks or files that cannot be read by the backup application in the live file system because of the changes that continue to occur in the live file system; and
determining a current name and/or path of the files or data blocks that could not be read by the backup application from the inode numbers stored in the current change log; and
changing the backup save set such that the backup save set is namespace consistent with the data blocks or files based on the current name and/or path of the data blocks.
13. The non-transitory computer readable medium of claim 12 , the method further comprising:
initiating the backup operation of the live file system; and
performing the backup operation while the live file system continues operation.
14. The non-transitory computer readable medium of claim 12 , the method further comprising storing the current change log with the backup save set.
15. The non-transitory computer readable medium of claim 12 , the method further comprising accessing the files that cannot be read based on the inode numbers associated with the files that cannot be read, wherein the inode numbers enable the backup application to determine a current path and name of the files that cannot be initially read such that the backup applicant can make the backup save set name space consistent with the live file system.
16. The non-transitory computer readable medium of claim 15 , the method further comprising further comprising:
opening the files and passing a reference to the newly opened files to the backup application; and
performing events that correspond to the newly opened files.
17. The non-transitory computer readable medium of claim 12 , the method further comprising wherein modifications to the files are stored in the change log.
18. The non-transitory computer readable medium of claim 12 , the method further comprising further comprising initiating the backup operation of the live file system without taking a snapshot of the live file system.
19. The non-transitory computer readable medium of claim 12 , the method further comprising further comprising ensuring that changes to the files that cannot be initially read are included in the backup save set of the live file system.