Assistance Needed with Backup Space Management in Veeam Backup for Office 365

[astoinemicro]

I am a new user of Veeam Backup for Office 365 and I'm encountering a challenge with managing backup space efficiently. I am backing up a Microsoft 365 tenant to a local disk with a capacity of 6 TB. However, I've noticed that the disk runs out of space quickly, reaching its limit after just one full backup and eight incremental backups.

My current setup in Veeam Backup for Office 365 is configured as follows:

Retention Policy: Snapshot-based retention for 10 years
Application of Retention Policy: Scheduled daily at 00:00
Given these parameters, I'm seeking guidance on how to better manage my backup strategy within the limited space of 6 TB, without the need to add additional storage. Any suggestions on optimizing the retention policy or other settings to conserve space would be greatly appreciated.

Thank you for your assistance and looking forward to your expert advice.

[Mildur]

Hello Morad

Please use our calculator to have an estimation of how much storage your backup server needs to store all your backups for 10 years: https://calculator.veeam.com/vb365
I cannot make any assumptions for you because I'm missing important factors such as the total size of your mailboxes, OneDrive Teams and SharePoint sites. And the expected change rate is also required.

Sizing M365 storage is not easy. One Drive storage per User could be 1TB if you don't limit it in the tenant. The users of that tenant can do daily changes and upload new files. which you have to protect with your VB365 server. Imagine 100 users changing 100GB per day. You can imagine yourself how fast this can fill up the storage

To calculate the storage requirement, make sure you are first aware of the expected change rate.

Best,
Fabian

PS:
Please note, our recommended storage solution is object storage for VB365. You will get a much better compression compared to repositories on local disk.
And object storage as a repository works more stable with VB365. New repository related features to optimize backup and restore job sessions may only be build for object storage repositories.

[Polina]

Hi Morad,

With your current setup, each restore point will be stored in the repository for 10 years, and with each increment, you will see data growth. Here you can read more about the specifics of this retention type, but in brief, on the first backup run VB365 takes all the historical data for the backed-up mailboxes, sites, etc., and saves it to the repository. This retention type is more space-consuming.

You can consider creating a new backup repository with item-level retention and a reduced retention period (if your business requirements allow for it). Item-level retention defines not only when and how the older data should be removed from the repository, but also what data should be backed up. It's based on the item's latest modification date, and, for example, with 1 year of retention, it will only back up items modified during the last year, thus consuming less space in the repository compared to snapshot-based retention.

On these forums, you can find multiple topics on retention types that might be helpful for you.

On top of that, please note that we highly recommend using object storage for repositories, as they give more scalability and provide more advanced functionality (like backup copy and more).

Thanks!