3-2-1 Rule

The 3-2-1 rule is fundamental when discussing data protection. This best practice advises maintaining:

Three copies of the data
Stored on two different media
With one copy stored off-site (and possibly offline)

These rules should be considered during the planning of your Microsoft 365 backup. Depending on the chosen storage architecture for your Veeam Backup for Microsoft 365 infrastructure, there are different strategies to adhere to the 3-2-1 design guideline.

Object Storage

The preferred storage technology for Veeam Backup for Microsoft 365 is Object Storage! When using Object Storage as the backup target, Veeam Backup for Microsoft 365 can create a copy of the backups in a secondary Object Storage location. In this secondary location, Veeam Backup for Microsoft 365 can leverage the Immutability functionality of the Object Storage platform, ensuring an immutable backup. The secondary backup copy can also utilize cost-effective storage classes such as Azure Blob Storage Archive access tier, Amazon S3 Glacier storage class, or Amazon S3 Glacier Deep Archive storage class.

Local Storage

When using Local Storage as the backup target, Veeam Backup for Microsoft 365 can’t create a Backup-Copy directly. To adhere to the 3-2-1 design guideline, you have two possible options:

Create a secondary backup job to write the Backup data to another backup repository.
Use Veeam Backup and Replication to create a backup of the entire Veeam Backup for Microsoft 365 implementation. Veeam Backup and Replication features application integration to ensure an application-consistent backup and allows single-item restores directly with the Veeam Explorers. More information on this solution can be found on Protect VB365.

Resources

Backup-copy Helpcenter information – Helpcenter page with details on Backup Copy
[Object replication for block blobs] - Object replication for block blobs
Protect VB365 – Protecting Veeam Backup for Microsoft 365 with Veeam Backup and Replication