A Synthetic Full Backup is an operation that combines data from prior Full and Incremental backups to produce a dataset that is indistinguishable from a Full Backup created at the time of the last Incremental job.

The concept of Synthetic Full Backup job is to perform Full backup of the system data only once and then perform subsequent incremental backup jobs. The backup sets obtained from the Incremental jobs and the Full backup jobs are then combined to produce a backup set that will replicate the backup set if a Full backup job was to perform on the last day the Incremental job was fired. Synthetic backup is an add-on feature which is added when the Advanced Disk-based Backup option is added.

A policy for Synthetic backup job will comprise of Full (baseline) job, Incremental job, and a Synthetic Full Backup.
Due to the interdependent nature of jobs and to exercise efficient control of data, Synthetic Full backup jobs must always be performed within a policy.
The use of policies is to establish and maintain proper runtime relationships between the jobs. An example Synthetic Policy is supplied under Job Setup | Policies.
To create a new policy for the Synthetic backup job, the following steps must be performed:

1. In the Backup Exec GUI, go to Job Setup and select New Policy from the Task Pane under Policy tasks. A dialogue box for New Policy (Figure 1) is displayed.

Figure 1
 


2. Select New template, at the template selection window select Backup Template (Figure 2) and click OK

Figure 2
 


3.  Under the General tab, select the backup method Full-Back up files -Using Archive bit (reset archive bit) and select the option Collect additional information for synthetic backup (Figure 3)

Select the device and media set and other options as per the requirements. The job can be fired to a Backup-to-disk folder or to a storage device.

Figure 3
 

5. Set schedule details and click OK

6. The template for a Full (baseline) job is created. Similarly, create a template for Incremental backup jobs. In this case, under the General tab | Backup method select Incremental - Backup changed files since last Full or incremental - Using archive bit (reset archive bit) (Figure 4) and select the option Collect additional information for synthetic backup.

The Incremental job can be targeted only to a Backup-to-Disk device. Select a Backup-to-disk folder under device selections.

Figure 4
 


7. Create a new template for Synthetic Backup (Figure 5), in the Template Selection window, select Synthetic Backup Template.
Select the device and media set and other options as per requirements.

Figure 5
 


9. The templates for the Synthetic Policy are created. The next step would be to set rules for proper runtime relationship between the jobs (Figure 6).

Figure 6
 


10. In the New Policy dialogue box, select New Rule. From the drop-down menu select the rules:

---Run <first template> only once where first template is Priming Full (Baseline) template

---If start time conflicts, <first template> will start and upon completion starts <second template>, where first template is Incremental backup template and the second template is Synthetic backup template.


11. Create a selection list that will be used with the Policy. Policies and selection lists are combined together to form Backup bobs. From the Task Pane under Job Setup, select New backup selection List (Figure 7). At the New Backup Selection List, select the drives or files and folders that are to be backed up. Give a suitable name for the selection list and click OK.

Figure 7
 


12. Right-click on the Policy for the Synthetic backup just created and select New Jobs using Policy (Figure 8) and select the selection list just created in step 11

Figure 8
 


13. Check the Job Monitor, the three jobs under the Synthetic Policy are scheduled (Figure 9)

Figure 9
 


The Jobs will run as per the Schedule and Rules defined in the Policy.

The following information must be noted while performing Synthetic Full Backup:

1. Incremental backup job can be fired only to the Backup-to-disk Folder

2. The Synthetic Full Backup will always be a Policy based job

3. The Synthetic Full Backup option is available only to NTFS volumes. The backup will fall back to traditional backup method on unsupported volumes or resources.