Unstructured Data Backups in Immutable Repositories
All the data stored in immutable repositories cannot be changed or deleted until the immutability period expires and the immutability lock for the data is released. The only exception is active metadata for backups stored in immutable hardened repositories and immutable deduplicating storage appliances (HPE StoreOnce and Dell Data Domain).
For more information on the structure of unstructured backup data in backup repositories, see the Data Structure in Backup, Archive and Secondary Repositories section.
How Immutability for Unstructured Backup Works
Immutability settings configured for a repository where you store unstructured data backups are applied to the whole backup of the unstructured data source, that is to all backup files protecting this source. Thus, the immutability configured for the repository starts its countdown for the backup files when Veeam Backup & Replication marks some old file versions and their data blocks for deletion according to the retention settings configured in the backup job. Files and data blocks are deleted from the backup repository when the immutability lock is released for them.
You can quickly roll back an unstructured data backup stored on an immutable backup repository to a point in time state by using the Sync-VBRNASBackupState PowerShell cmdlet.
The period of the immutability lock for unstructured data backups in hardened repositories and immutable deduplicating storage appliances (HPE StoreOnce and Dell Data Domain) is defined by the immutability settings of those backup repositories.
For an example of how this mechanism works, see Case 8 in the Unstructured Data Backup Retention Scenarios section. For more information on hardened repositories and on how to configure them, see the Hardened Repository section. For more information on how to configure immutability for HPE StoreOnce, see the HPE StoreOnce section, for Dell Data Domain — the Dell Data Domain section.
For general information on the immutability feature for object storage repositories in Veeam Backup & Replication and on how to configure it, see the Immutability for Object Storage Repositories section.
Apart from the immutability period set for each object storage repository, Veeam Backup & Replication automatically adds up to 10 days to the immutability expiration date to reduce I/O operations and associated costs. This period is called Block Generation. You do not have to configure it, the Block Generation setting is applied automatically. For example, if you set your immutability period to 14 days for your object storage repository, Veeam Backup & Replication adds 10 days to specific objects to reduce I/O operations with the data blocks over time. Thus, you will have immutability set to 14 days plus 10 days of Block Generation set for data blocks in your object storage repositories, so the actual immutability period will equal to 24 days.
For an example of how this mechanism works, see Case 9 in the Unstructured Data Backup Retention Scenarios section. For more information, see the Block Generation section for object storage repositories.
We strongly recommend the following configuration for storing unstructured data backups in immutable object storage repositories:
Otherwise, the unstructured data backup may consume too much storage space.
These settings are critical for cloud object storage repositories where the cost of the disk space consumed for storing file versions may be very high.
Metadata of Unstructured Data Backups in Immutable Storage Repositories
When creating unstructured data backups in the backup repository, Veeam Backup & Replication creates two sets of metadata: active metadata and the metadata replica. Metadata replica is always stored in the backup repository next to the data. As for the active metadata, it can be stored on different infrastructure components depending on the type of the backup repository used to store backups:
- If you store your backups in a hardened repository or deduplicating storage appliance (HPE StoreOnce or Dell Data Domain), the active metadata is stored on the immutable repository alongside with the locked metadata replica and locked backup data.
- If you store your backups in an object storage repository, the active metadata is stored on the cache repository.
Data in immutable repositories is temporarily locked and cannot be changed or removed till the immutability period ends. The metadata replica that is stored next to the data is also immutable and cannot be changed. But the active metadata does not have the immutability lock. So it changes actively during every backup session and keeps the up-to-date state of the unstructured data backup. Thus, it can be used by Veeam Backup & Replication to track changes in the unstructured data backup.
Once in 30 days (if the job runs once a day or once in several days) or as the metadata replica chain reaches 30 generations (if the job runs several times a day), Veeam Backup & Replication uses metadata replica files created during this period to generate a new locked metadata flat file.
After the immutability period for the metadata replica files, which were already transformed into the metadata flat file, ends, Veeam Backup & Replication removes them from the object storage repository.
The schemas below show examples of creating a locked metadata flat file for a job that runs once every day. After 30 generations of metadata replica files are created (that is after 30 days), Veeam Backup & Replication uses them to generate a new metadata flat file. The older metadata replica files that comprised it are marked for deletion and can be deleted based on the retention and immutability settings of the repository.
Metadata in Hardened Repositories and Immutable Deduplicating Storage Appliances
If unstructured data backups are stored in an immutable hardened repository or deduplicating storage appliance (HPE StoreOnce or Dell Data Domain), the active metadata is stored on the immutable repository alongside with the locked metadata replica and locked backup data.
Metadata in Immutable Object Storage Repositories
If unstructured data backups are stored in an immutable object storage such as Amazon S3, Microsoft Azure Storage, IBM Cloud Object Storage, Wasabi Cloud Object Storage, or S3-compatible object storage, the active metadata is stored on the cache repository.