Utilizing image backup to perform file system incremental backup

There are two methods of utilizing image backups to perform efficient incremental backups of your file system. These backup methods allow you to perform point-in-time restore of your file systems and improve backup and restore performance.

You can perform the backup only on formatted volumes; not on raw logical volumes. You can either use image backup with file system incremental or you can use image backup with image incremental mode to perform image backups of volumes with mounted file systems.

The following are some examples of using image backup with file system incremental.

To perform a full incremental backup of the file system: dsmc incremental /myfilesystem
To perform an image backup of the same file system: dsmc backup image /myfilesystem
To periodically perform incremental backups: dsmc incremental /myfilesystem

To perform a full incremental backup of the file system: dsmc incremental h:
To perform an image backup of the same file system: dsmc backup image h:
To periodically perform incremental backups: dsmc incremental h:

You must follow the next steps in the order shown to ensure that the server records additions and deletions accurately.

AIX operating systems HP-UX operating systems Linux operating systems Oracle Solaris operating systems Use this command to restore the file system to its exact state as of the last incremental backup: dsmc restore image /myfilesystem -incremental -deletefiles.

Windows operating systems Use this command to restore the file system to its exact state as of the last incremental backup: dsmc restore image h: -incremental -deletefiles.

During the restore, the client does the following:

Restores the most recent image on the server.
Deletes all of the files restored in the previous step which are inactive on the server. These are files which existed at the time of the image backup, but were subsequently deleted and recorded by a later incremental backup.
Restores new and changed files from the incremental backups.

If you do not follow the steps exactly, two things can occur:

After the original image is restored, all files backed up with the incremental command are restored individually.
If you perform a backup image before performing an incremental, files deleted from the original image are not deleted from the final restored file system.

The following are some examples of using image backup with image incremental mode.

To perform an image backup of the same file system: dsmc backup image /myfilesystem
To perform an incremental image backup of the file system: dsmc backup image /myfilesystem -mode=incremental
This sends only those files that were added or changed since the last image backup to the server.
To periodically perform full image backups: dsmc backup image /myfilesystem
To restore the image: dsmc restore image /myfilesystem -incremental
On restore, Tivoli® Storage Manager ignores the deletefiles option when the image+image incremental technique of backing up has been used. The restore will include files that were deleted after the last full image backup plus the latest versions of files added or changed after the last image backup.

To perform an image backup of the same file system: dsmc backup image h:
To perform an incremental image backup of the file system: dsmc backup image h: -mode=incremental
This sends only those files that were added or changed since the last image backup to the server.
To periodically perform full image backups: dsmc backup image h:
To restore the image: dsmc restore image h: -incremental
On restore, Tivoli Storage Manager ignores the deletefiles option when the image+image incremental technique of backing up has been used. The restore will include files that were deleted after the last full image backup plus the latest versions of files added or changed after the last image backup.

Note: You should perform full image backups periodically in the following cases. This will improve restore time because fewer changes are applied from incrementals.

When a file system changes substantially (more than 40%).
Once each month.
As appropriate for your environment.

The following restrictions apply when using the image backup with image incremental mode:

The file system can have no previous full incremental backups produced by the incremental command.
Incremental-by-date image backup does not inactivate files on the server; therefore, when files are restored, none can be deleted.
If this is the first image backup for the file system, a full image backup is performed.
Using mode=incremental backs up only files with a changed date, not files with changed permissions.
If file systems are running at or near capacity, an out-of-space condition could result during the restore.