Understand: How much time does it take to complete a backup?
What to keep in mind when the backup system is completing a backup job:
The first backup always takes the longest, as it’s processing all data within your Microsoft 365 tenant. The time it takes to complete a backup job is also depended on the number of objects, as well as the number of items within each object. An object can be a SharePoint site, a user-mailbox, or a OneDrive user. Items can be files, mails, contacts, etc.
When the first backup is complete and the next run of the backup job occurs, it does not take as long as with the initial backup, as these are incremental and not a full job – meaning that only new objects are added.
Another thing to bear in mind is that Microsoft only allow two applications (applications in Microsoft 365 tenant) to pull data from M365 to us. Moreover, Microsoft throttles the connection speed, meaning they decide what speed, which data is downloaded – and the time it takes to complete a full backup. In other words, connection speed varies because of this, and this does applies to all providers of solutions, which integrate with Microsoft and for other backup services this will be the same experience.