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Synthetic Full Backup

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In some situations, running active full backups periodically may not be an option. Full backups are very resource-intensive and consume considerable amount of network bandwidth. As an alternative, you can create synthetic full backups.

In terms of data, the synthetic full backup is identical to a regular full backup. The synthetic full backup is a .vbk file that contains data of the whole VM. The difference between these two backup types lies in the way how VM data is retrieved:

When you perform full backup, Veeam Backup & Replication retrieves VM data from the source datastore (volume) where the VM resides, compresses and deduplicates it and writes it to the VBK file in the backup repository.
When you perform synthetic full backup, Veeam Backup & Replication does not retrieve VM data from the source datastore (volume). Instead, it “synthesizes” a full backup from data you already have in the backup repository. Veeam Backup & Replication accesses the previous full backup file and a chain of subsequent increments in the backup repository, consolidates VM data from these files and writes consolidated data into a new full backup file. As a result, the created synthetic full backup file contains the same data you would have if you created a full backup in a regular manner.

Veeam Backup & Replication treats a synthetic full backup as a regular full backup. As well as any other full backup, the synthetic full backup resets the chain of increments. All subsequent increments use the created synthetic full backup as a new starting point. A previously used full backup file remains on disk until it is automatically deleted according to the backup retention policy.

The synthetic full backup has a number of advantages:

The synthetic full backup does not use network resources: it is created from backup files you already have on disk.
The synthetic full backup imposes less load on the production environment: it is created right in the backup repository.

With Veeam Backup & Replication, you can schedule creation of synthetic full backups on specific days.