BTRFS eats my diskspace

[adoII]

Hi,

I recently installed a proxmox server with local-btrfs
It is a 2 Disk raid 1 with size 1.8 TB
btrfs fi usage / tells me that 1.67 TB are in use
In fact only 934 GB are in Files on the disk
When checking the diskspace with the btrfs tool btdu I can see that the disk space of the vms is counted nearly twice.
The tool says 922 GB are used in /var/lib/pve/local-btrfs and another 680 GB are in RAID1/DATA/UNREACHABLE/var/lib/pve/local-btrfs
These UNUSED are the 680GB Disk Space I am missing

Does anyone know what is happening and how I can relaim my 680GB UNREACHABLE Disk Space ?

 

[adoII]

To answer my question, long story short:

btrfs fi defrag 103/vm-103-disk-0/disk.raw

After all I read about btrfs i came to the conclusion to not use btrfs for vm images again in the next years