The long-term or Grandfather-Father-Son (GFS) retention policy allows you to store backup files for long periods of time — for weeks, months and even years. For this purpose, Veeam Backup & Replication does not create any new backup files — it uses backup files already created and marks them with specific GFS flags.
To mark a backup file for long-term retention, Veeam Backup & Replication can assign to the file the following types of GFS flags: weekly (W), monthly (M) and yearly (Y). The types of GFS flags that Veeam Backup & Replication assigns depend on the configured GFS retention policy settings.
GFS flags can be assigned only to full backup files created during the time period specified in GFS policy settings.
As soon as Veeam Backup & Replication assigns a GFS flag to a full backup file, this backup file can no longer be deleted or modified. Also, Veeam Backup & Replication does not apply short-term retention policy settings to the full backup file — that is, Veeam Backup & Replication ignores the backup file when determining whether the number of allowed backup files is exceeded.
When the specified retention period ends, Veeam Backup & Replication unassigns the GFS flag from the full backup file. If the backup file does not have any other GFS flags assigned, it can be modified and deleted according to the short-term retention policy.
When planning to use the GFS retention policy, mind the following limitations:
- GFS retention policy does not apply to reverse incremental backup chains.
- GFS retention policy applies to forever forward incremental backup chain only if you periodically create full backups manually or using scheduled scripts. For more information on cmdlets that you can use in scripts, see the Veeam PowerShell Reference Guide.
- As Veeam Backup & Replication does not create new full backup files while applying the GFS retention policy, you must configure your backup jobs in a way you do not lose any essential data due to an insufficient number of full backup files. For example, if you configure monthly GFS retention, you need at least one full backup file per month.
- If a GFS flag is assigned to a full backup file in an active backup chain, the following applies:
- Veeam Backup & Replication cannot transform the backup chain.
- Veeam Backup & Replication is not able to merge data from incremental backup files into the full backup file. For forever forward incremental backup chain, this means, that the short-term retention policy does not apply.
- Retention policy for deleted items does not apply.