The synthetic backup feature eliminates the need to perform recurring full backups for supported remote resources. A policy created for the synthetic backup feature enables the synthetic backup to be assembled from a full backup (called a baseline) and subsequent incremental backups that are also contained in the policy.

The resulting synthetic backup then becomes the new baseline, so only incremental backups are required until the next synthetic backup is created. The synthetic backup is as current as the last incremental backup that it contains.

The components of the policy for synthetic backup are:

a. Baseline. The first backup to run that is associated with the synthetic backup. The baseline backup runs one time only, and will always back up all of the files on the selected resources when it runs.

b. Recurring incremental backups. Subsequent backups that back up files that are changed after the baseline backup. After the baseline backup completes, at least one incremental backup is necessary.

c. Recurring synthetic backups. The process that combines the data from the baseline backup and the incremental backups to form a synthesized full backup of the selected resources. This synthesized full backup becomes a new baseline backup, which can then be combined with subsequent incremental backup sets to form the next synthesized full backup.

Synthetic backups can only be created within a policy. You can use the Policy Wizard to create a policy that will contain the necessary job templates for the synthetic backup feature, or you can copy the example policy for synthetic backup and then modify it to suit your specific needs, or you can manually create a policy, and then add the necessary job templates.

For all of the associated synthetic backup templates in a policy, you can also use a Duplicate Backup Set template to create a multi-stage backup strategy for backing up data to disk and then copying it to tape.


The following are the Requirements for the Synthetic Backups:

1. Synthetic backups and their associated templates can only be created in policies.

2. Backup templates that create incremental backup jobs must have Backup-to-Disk folders as destination devices. Before you can save a policy that contains the synthetic backup templates, you must have a Backup-to-Disk folder that you can select as the destination device for the required incremental backup jobs.

Additionally, in order for the example policy for synthetic backup to be displayed after installation, you must create a Backup-to-Disk folder when the First Time Startup Wizard is run.

If the example policy for synthetic backup is not displayed, create a Backup-to-Disk folder, and then on the Tools menu, click Re-create Example Policies. ( Figure 1)
The example policy will be displayed in the Policies pane in the Job Setup view.

Figure 1.
 

 

3. The option Collect additional information for synthetic backup must be selected for backup templates for incremental and full backup jobs created for synthetic backup. This option is on the General page of the Backup Job Template properties.(Figure 2)
Figure 2.
 

4. If the baseline backup job was written to tape, and if you also want to write the synthetic backup job to tape, two tape drives are required: one to mount the source job on (the baseline backup) and one to mount the destination job on (the synthetic backup job).


Following are Limitations when running synthetic backups:

1. Only file system resources are supported for synthetic backup. If a backup selection list contains resources that are not supported, such as databases, and the selection list is associated with a policy that contains the synthetic backup template, the jobs for the synthetic backup will not be created.

2. If the Central Admin Server Option is installed, the synthetic backup job template and any associated full and incremental job templates must be run on destination devices that can all be accessed by the media server that runs the synthetic backup job.