Problem description
The size of inSync’s backup is less than the actual size of the site in Microsoft 365.
This leads to a concern with the customers, whether we are backing up all the data or not.
Cause
Versioning creates a historical record of all changes, with the date/time and an indication of the user who made the change, on a per-file/list item basis.
Steps to validate
Check for Versioning.
Steps to check Versioning:
Log on to the concerned Site Collection.
Go to the document library >> Click the Library tab on the Ribbon >> Click on Library Settings.
Under General Settings, click the Versioning Settings link.
Check if “Create a version each time you edit a file” is enabled or not:
❗ Important
If versioning is enabled, inSync can back up only the latest version of each file. But SharePoint online usage will show the total size of all the versions included, which leads to the data usage difference between inSync and SharePoint Online.
What we know about SharePoint Versioning ( MS Documentation )
Sharepoint Online Versioning acts like a backup within Sharepoint Online, where if a user modifies a file, SharePoint will keep the original version of the file as well.
Under Site Contents, you will only see the total count of files and folders, but the count of versions is not available.
Versions can only be seen if you go to the Version History of the files.
Versions calculate towards the total storage space consumption in SharePoint.
If there are any questions or need assistance, please contact the support team via support.druva.com