Backup data size

[adam900331]

Hy!

I have a backup repository where the backup data is stored. This is the Windows based repository. The D: volume is ReFS and the total capacity is 10,9Tb. The total used space is 6,4Tb.

When I enter the D: volume there are some folder, like Backup. The Backup folder stores all of the backup data. When I check the Backup folder size, I see that the total size is 13,9Tb. How is it possible?

When I check it on the Veeam console side under the Backup Repositories:
Capapcity: 10,9Tb
Free: 4,4Tb
Used Space: 13,7Tb

Thanks.

[d.artzen]

ReFS is capable of using "Block Cloning", that is one of the advantages over NTFS. Veeam uses this for their "Fast Clone" feature, which allows for smaller backup sizes in specific circumstances like "Synthetic Full" Backups. It is described in the user guide here: https://helpcenter.veeam.com/docs/vbr/u ... tml?ver=13
In practice this means you need less space than the backup would normally need on an NTFS volume. On a linux repository this is also possible if for example XFS is used as the filesystem, so this is not specific to Windows.