Veeam Immutability Explained
Summary
This article describes what immutability backups are and how they work.
What is immutability?
Immutability is the state of data that prevents it from being modified or deleted. Veeam Backup & Replication applies immutability to the state of a backup chain within a certain period of time. After you enable immutability, Veeam Backup & Replication prohibits deleting data from object storage repositories until the immutability expiration date comes. Immutability settings configured for object storage repository are applied to the whole backup chain and all its restore points.
Effect on job retention?
Immutability affects both backup jobs AND backup copy jobs.
When you configure an object storage repository, keep in mind that the immutability period affects the total number of restore points stored in the object storage repository. Although the immutability period does not depend on the retention of the backup chain, it will preserve more restore points in addition to the restore points stored according to a retention policy to guarantee consistency of earlier states of the backup chain and the ability to roll back to it.
Formula = Job retention period + immutability period
Example: A backup job with 30 days retention → 30 + 7 = 37 days
Example Scenario
We have a backup job configured with the following settings:
Backup job with a retention of 7 days
Immutability set to 7 days (lowest possible)
For the sake of the example, we start on the 1st of the month.
The whole chain of backups, including 1 full backup and 6 incremental backups will be kept immutable until the 14th of the month.
You cannot delete full backups which still have an incremental backup depending on it.
Date (month) | Chain | Type | Time of deletion (month) | Comment |
---|---|---|---|---|
1st | 1 | Full 1:0 | 15th | Deleted after 3:0 creation |
2nd | 1 | Incremental 1:1 | 15th | Dependent on 1:0 |
3rd | 1 | Incremental 1:2 | 15th | Dependent on 1:0 |
4th | 1 | Incremental 1:3 | 15th | Dependent on 1:0 |
5th | 1 | Incremental 1:4 | 15th | Dependent on 1:0 |
6th | 1 | Incremental 1:5 | 15th | Dependent on 1:0 |
7th | 1 | Incremental 1:6 | 15th | Dependent on 1:0 |
8th | 2 | Full 2:0 | 22th | Deleted after 4:0 creation |
9th | 2 | Incremental 2:1 | 22th | Dependent on 2:0 |
10th | 2 | Incremental 2:2 | 22th | Dependent on 2:0 |
11th | 2 | Incremental 2:3 | 22th | Dependent on 2:0 |
12th | 2 | Incremental 2:4 | 22th | Dependent on 2:0 |
13th | 2 | Incremental 2:5 | 22th | Dependent on 2:0 |
14th | 2 | Incremental 2:6 | 22th | Dependent on 2:0 |
15th | 3 | Full 3:0 | 29th | Deleted after 5:0 creation |