File-level continuous data protection with access to previous versions
View Patent ↗A system for continuous data protection includes a storage device and a backup storage device. The continuous data protection procedure is performed as two parallel processes: creating an initial backup by copying a data as a file/directory from the storage device into the backup storage device, and copying the data to be written to the data storage as a part of a file/directory into the incremental backup. When a write command is directed to a file system driver, it is intercepted and redirected to the backup storage, and the data to be written in accordance with the write request, is written to the incremental backup on the backup storage. If the write command is also directed to a data (a file/directory) that has been identified for backup, but has not yet been backed up, the identified data (a file/directory) is copied from the storage device to the intermediate storage device. Then, the write command is executed on the identified file/directory on the storage device and the file/directory is copied from the intermediate storage device.
1. A method for continuous data protection on a computer system, the method comprising:
creating a list of protected data objects and a list of objects excluded from protection, the protected data objects having a plurality of data-sets, the data objects being files or folders;
creating a full file-level backup of the protected data objects;
generating intermediate pass-through snapshots for the protected data objects during a write attempt into an open protected data object, wherein the pass-through snapshot includes identifiers of the data-sets and a bitmap reflecting changes in the data-sets of the protected data objects;
creating active snapshots based on the pass-through snapshots, the active snapshots reflecting latest states of the protected objects; and
creating incremental backups from the active snapshots, wherein each pass-through snapshot has a plurality of control bits assigned to each of the data-sets in the bitmap and wherein the control bits indicate that the data-set has been changed during a continuous data protection period that begins when a write file request is received.
2. The method of claim 1 , wherein states of the backed data are viewable at a point of creation of the active snapshot used for creation of the backup.
3. The method of claim 1 , wherein the list of protected data objects is generated based on a list of objects excluded from protection.
4. The method of claim 1 , wherein the backed up data objects are restored from the backup individually.
5. The method of claim 1 , wherein the backed up data objects are restored from the backup as a group.
6. The method of claim 1 , wherein all backed up objects are restored after a restoration of the full backup.
7. The method of claim 1 , wherein all backed up objects are restored after a restoration of system and loading areas of a storage media.
8. The method of claim 1 , wherein the full backup is created at a file-level.
9. The method of claim 1 , wherein the full backup is created at a block-level.
10. The method of claim 1 , wherein the pass-through snapshot comprises a bitmap of data-sets corresponding to at least one protected object.
11. The method of claim 1 , wherein the pass-through snapshot comprises data-sets of at least one protected object.
12. The method of claim 1 , wherein the pass-through snapshot comprises a name of at least one protected object.
13. The method of claim 1 , wherein the active snapshot comprises data-sets of at least one protected object.
14. The method of claim 1 , wherein the active snapshot is a copy of the pass-through snapshot.
15. The method of claim 1 , wherein the pass-through snapshot is generated when a protected object is opened.
16. The method of claim 1 , wherein the active snapshot is generated when a protected object is closed.
17. The method of claim 1 , wherein the active snapshot is generated periodically for open files.
18. The method of claim 1 , wherein the full file-level backup of the protected data objects is created after the computer system is started.
19. The method of claim 1 , wherein the full file-level backup of the protected data objects is created prior to shutdown of the computer system.
20. A system for continuous data protection, the system comprising:
a file system that stores data objects comprising data-sets on a storage media, the data objects being files or folders;
a file system driver that services the file system;
a storage media for storing the file system data, the storage media connected to the file system driver; and
a file system filter that monitors changes in the file system having a set of protected data objects that are being monitored,
wherein the file system filter redirects, to backup storage, the data-sets of data objects modified prior to the modification, and overwrites the portions with new data, and wherein:
intermediate pass-through snapshots are created for all protected data objects during a write attempt into an open protected data object, each pass-through snapshot includes identifiers of the data-sets and a bitmap having a plurality of control bits assigned to each of the data-sets, wherein the control bits indicate that the data-set has been changed during continuous data protection period that begins when a write file request is received by the file system filter;
active snapshots, reflecting latest states of the data objects, are created based on the pass-through snapshots; and
incremental backups are created from the active snapshots.