Symptoms
Cloud storage is overused by backups of M365 (Teams, One Drive, etc) or Google Workspace (Google Drive).
Backup storage size is several times bigger than the backed up data.
Cause
There are multiple causes why the C2C backups consume significantly more storage space than the data being backed up. Data handling works differently because of some peculiarities of the source storage itself.
1) Data deleted from the source is still included in the backup
For example, when you have 10Gb on Google Drive and you do a backup - you will have a 10 Gb archive.
When you delete 1Gb from Google Drive, and do another backup, you will have 9 Gb on Google Drive and a 10Gb archive, because deleted data is still packed into it.
2) Renamed files are backed up as new.
Even if the data was not deleted but just renamed, renamed data will be backed up twice, because Backup Agent treats the renamed data as new.
For example, you have a 1 Gb file, and you do a backup, and you have a 1 Gb archive. If you rename the source file, you will have 1Gb on Google drive, and 2 Gb archive, thus it is not always just to compare the size of the source and the size of the archive.
3) Shared folder is backed up for each user.
If you have a folder on this drive that is used by many participants, the files inside will be backed up as many times as they are changed by all of the participants who have access to it - once for every participant.
Additionally, in Google Workspace, check if data to back up is placed in personal drives using multiple location features: this feature was deprecated by Google in September 2020, and was replaced by shortcuts.
For more information please see:
Please verify if you have a legacy configuration that uses multiple locations. If so, we suggest replacing the shared folders by shortcuts (for all of the users). In this case, API will not return changes in the shared folders during the user drive backup, and we will not backup shared data for all users.
To avoid inflating backup size due to using shared drives, you can also use the following workaround:
- Create a group backup plan for Google Workspace users.
- Add all shared folders to the exclusions: see Selecting Google Drive Files.
- To protect the shared folder(s), create a separate backup plan for 1 user without exclusions.