For every user, which has access to the sharepoint site, you will need a license. Guest users are excluded from that.
If all 100 users has access to the sharepoint sites, you need to have to buy 100 licenses.
The same license will be used for backup of the 40 users own mailbox and onedrive.
Additionally, each user in your Office 365 subscription (or on-premises deployment) that has been granted access to team, communication, collaboration and other non-personal SharePoint sites that you plan to back up must be licensed.
NOTE :
When you plan a number of units in your Veeam license, consider the following:
1) All users in your Microsoft 365 subscription or on-premises deployment that are members of a backed-up team or have access to a backed-up team, communication, collaboration and other non-personal SharePoint sites must be licensed. If you have a hybrid SharePoint deployment (on-premises Microsoft SharePoint and SharePoint Online), and the same user has access to both, then only one Veeam license is required.
2) If you back up only Microsoft Teams objects or non-personal SharePoint sites, the Veeam license units are not consumed by Veeam Backup for Microsoft 365.
As point 1 and 2 are the opposite of each other, in the case where no mailboxes, no OneDrive and no Personal SharePoint are backed up, that means no Veeam M365 licences are needed ?
Even if 200 users have access accross the SPO sites ?
@Mildur
Could we get an answer to Seb's question above? I have been asked the same but can't answer it as the explanation from veeam is pretty missleading.
Yes, A license is required by every user who has access to protected objects.
But Veeam Backup for Microsoft 365 will not consume a license instance.
Why is that not happening? When you are protecting a SharePoint Site, we would have to enumerate every single security group and user account who has access to that SharePont side.
Then for each security groups, we would have to resolve it into single users. That adds additional processing times to our backup jobs. It also requires many more API calls which may lead to more throttling from Microsoft. That's why we have decided to not implement consumption tracking when you protect SharePoint sites or Teams.
Remember the old Active Directory or Exchange days, where you had to actually buy Active Sync and Exchange User CALs. But you didn't had to install them on the Exchange Server. There was no license counter in the product and no "license was consumed".
In case of a license audit you had to provide a paper with the User CAL amount to the license auditor.
Summarized:
- According to our license policy, you must buy licenses for every user who has access to a protected object
- On the technical site, License consumption will stay at 0 because we are not enumerating all accounts with access
Technically you can install a license for 1 user and protect hundreds of SharePoint Sites. But you would violate our license policy.