Immutability

Veeam Backup for Microsoft 365 allows you to prohibit deletion of backup copies from object storage by making that data temporarily immutable. It is done for increased security: immutability protects your data from loss as a result of attacks, malware activity or any other injurious actions that may be performed by 3rd party applications.

You can enable immutability when adding object storage to Veeam Backup for Microsoft 365. Keep in mind that object storage with enabled immutability can be used only to store backup copies. The immutability period matches the duration of applying the retention policy configured for the backup repository which is extended with such object storage. Data will be blocked for deletion or modification for the period of applying the retention policy. For more information, see Specify Retention Policy Settings.

Veeam Backup for Microsoft 365 extends the immutability period in the following ways:

If the extended backup repository has the snapshot-based retention type, the duration of the immutability period for backup copies stored in object storage will be prolonged only for those parts of a snapshot for which retention policy still can be applied.
If the extended backup repository has the item-level retention type, the duration of the immutability period for backup copies stored in object storage will be prolonged only for those objects for which retention policy still can be applied.

Before You Begin to Use Immutability

In order to use immutability for backed-up data that you want to store in Amazon S3, Amazon S3 Glacier and S3 Compatible object storage, you must enable the Object Lock and Versioning features on your Amazon S3 bucket and S3 Compatible bucket at the time you create the bucket. Keep in mind that most vendors allow enabling Object Lock only at the moment of creating the bucket. Once imposed, the Object Lock prohibits deletion of data from object storage until the immutability period ends.

For more information, see these Amazon articles:

If you want to use immutability for backed-up data that you want to store in Microsoft Azure Blob Storage, you must enable Versioning for the Microsoft Azure Blob storage account that you want to use and select the Enable version-level immutability support check box when creating the Azure container.