Does Veeam backup unused space

[andreas2012]

Hi,

If I have a VM that has a disk 1TB, and only 500GB of data.
If I create a full backup, with optimal compression, will a full backup be 500GB, 1TB or less ?

What my main question is, does it backup empty disk space ? If backs up empty disk space, I guess i will just compress it so good it will not matter...

/Regards
Andre

[Mildur]

Hi Andre

Yes, veeam will not backup the empty disk space (no data, no deleted datablocks). The fullbackup will be taken from the 500GB used space. This is only valid for windows filesystems.

If the unused 500GB data contains deleted datablocks, it depends on the filesystem you have used if they are backed up or not.
If you are using NTFS as the guest filesystem, veeam can exclude them. The feature is called Bitlooker.
If you have REFS or FAT as the guest filesystem, veeam cannot exclude the deleted data blocks and they will be backed up.

[AlexHeylin]

Thanks @Mildur - I learned something today (that Bitlooker only works on NTFS).