In the Retention Rules window, you can select how long to store backups in the location and whether to move or delete them afterward.
The rules will be applied to all the backups taken on the specific machine and put in this specific location by this specific backup plan. In Acronis Backup & Recovery 11, such set of backups is called an archive.
To set up retention rules for backups:
Specify one of the following (options (a) and (b) are mutually exclusive):
A backup will be stored until the specified condition (or both of the conditions) are met.
Example:
Backups older than5 days
Archive size greater than 100 GB
With these settings, a backup will be stored until it is older than five days and the size of the archive containing it exceeds 100 GB.
Number of backups in the archive exceeds...
If the number of backups exceeds the specified value, one or more of the oldest backups will be moved or deleted. The minimal setting is 1.
Select whether to delete the backups or to move them to another location if the specified conditions are met.
You will be able to specify the location where to move the backups and set up retention rules for that location after you click OK.
Deleting the last backup in the archive
The retention rules are effective if the archive contains more than one backup. This means that the last backup in the archive will be kept, even if a retention rule violation is detected. Please do not try to delete the only backup you have by applying the retention rules before backup. This will not work. Use the alternative setting Clean up archive > When there is insufficient space while backing up if you accept the risk of losing the last backup.
To access this setting, click Show advanced settings in the Retention Rules window.
Retention rules presume deleting or moving some backups while retaining the others. What if the archive contains incremental and differential backups that depend on each other and on the full backups they are based on? You cannot, say, delete an outdated full backup and keep its incremental “children”.
When deletion or movement of a backup affects other backups, one of the following rules is applied:
Retain the backup until all dependent backups become subject to deletion (movement)
The outdated backup will be kept until all backups that depend on it also become outdated. Then, all the chain will be deleted at once during the regular cleanup. If you chose moving outdated backups to the next location, the backup will be copied there without delay. Only its deletion from the current location is postponed.
This mode helps to avoid the potentially time-consuming consolidation but requires extra space for storing backups whose deletion is postponed. The archive size and/or the backup age or number can exceed the values you specify.
Consolidate these backups
The software will consolidate the backup that is subject to deletion or movement, with the next dependent backup. For example, the retention rules require to delete a full backup but to retain the next incremental one. The backups will be combined into a single full backup which will be dated with the incremental backup date. When an incremental or differential backup from the middle of the chain is deleted, the resulting backup type will be incremental.
This mode ensures that after each cleanup the archive size and the age or number of backups are within the bounds you specify. The consolidation, however, may take a lot of time and system resources. You still need some extra space in the vault for temporary files created during consolidation.
What you need to know about consolidation
Please be aware that consolidation is just a method of deletion but not an alternative to deletion. The resulting backup will not contain data that was present in the deleted backup and was absent from the retained incremental or differential backup.
Deleting or moving backups with dependencies