[PVE-User] Analysis of free space...

[Matthieu Dreistadt]

Hi Marco,

you can check "zfs list -o space", which will give you a more detailed 
view of what is using the space:

root at xxx:~# zfs list -o space
NAME                          AVAIL   USED  USEDSNAP  USEDDS 
USEDREFRESERV  USEDCHILD
rpool                          507G   354G        0B    104K      0B    
    354G
rpool/ROOT                     507G  4.40G        0B     96K      0B    
   4.40G
rpool/ROOT/pve-1               507G  4.40G     1.05G   3.35G      0B    
      0B
rpool/data                     507G   312G        0B    112K      0B    
    312G
rpool/data/subvol-105-disk-0  8.62G  11.4G     49.2M   11.4G      0B    
      0B

Used = overall used
Usedsnap = Used by Snapshots
Usedds = Used Disk Space (not counting snapshots, only live data)
Usedchild = Used by datasets/zvols further down in the same path (in my 
example, rpool has the same amount of Used and Usedchild space, since 
there is nothing directly inside of rpool itself)

Cheers,
Matthieu

Am 24.09.2025 um 18:29 schrieb Marco Gaiarin:
> Mandi! Marco Gaiarin
>    In chel di` si favelave...
>
>> Uh, wait... effectively we forgot to enable 'discard' on volumes, and we have
>> enabled afterward (but rebooted the VM).
>> I'll check refreservation property and report back.
> No, volumes seems have all refreservation to 'none', as expected; current
> situation is:
>
>   root at lamprologus:~# zfs list | grep ^rpool-data
>   rpool-data                  54.2T  3.84T   171K  /rpool-data
>   rpool-data/vm-100-disk-0    1.11T  3.84T  1.11T  -
>   rpool-data/vm-100-disk-1    2.32T  3.84T  2.32T  -
>   rpool-data/vm-100-disk-10   1.82T  3.84T  1.82T  -
>   rpool-data/vm-100-disk-11   2.03T  3.84T  2.03T  -
>   rpool-data/vm-100-disk-12   1.96T  3.84T  1.96T  -
>   rpool-data/vm-100-disk-13   2.48T  3.84T  2.48T  -
>   rpool-data/vm-100-disk-14   2.21T  3.84T  2.21T  -
>   rpool-data/vm-100-disk-15   2.42T  3.84T  2.42T  -
>   rpool-data/vm-100-disk-16   2.15T  3.84T  2.15T  -
>   rpool-data/vm-100-disk-17   2.14T  3.84T  2.14T  -
>   rpool-data/vm-100-disk-18   3.39T  3.84T  3.39T  -
>   rpool-data/vm-100-disk-19   3.40T  3.84T  3.40T  -
>   rpool-data/vm-100-disk-2    1.32T  3.84T  1.32T  -
>   rpool-data/vm-100-disk-20   3.36T  3.84T  3.36T  -
>   rpool-data/vm-100-disk-21   2.50T  3.84T  2.50T  -
>   rpool-data/vm-100-disk-22   3.22T  3.84T  3.22T  -
>   rpool-data/vm-100-disk-23   2.73T  3.84T  2.73T  -
>   rpool-data/vm-100-disk-24   2.53T  3.84T  2.53T  -
>   rpool-data/vm-100-disk-3     213K  3.84T   213K  -
>   rpool-data/vm-100-disk-4     213K  3.84T   213K  -
>   rpool-data/vm-100-disk-5    2.33T  3.84T  2.33T  -
>   rpool-data/vm-100-disk-6    2.28T  3.84T  2.28T  -
>   rpool-data/vm-100-disk-7    2.13T  3.84T  2.13T  -
>   rpool-data/vm-100-disk-8    2.29T  3.84T  2.29T  -
>   rpool-data/vm-100-disk-9    2.11T  3.84T  2.11T  -
>
> and a random volume (but all are similar):
>
>   root at lamprologus:~# zfs get all rpool-data/vm-100-disk-18 | grep refreservation
>   rpool-data/vm-100-disk-18  refreservation        none                   default
>   rpool-data/vm-100-disk-18  usedbyrefreservation  0B                     -
>
> Another strange thing is that all are 2TB volumes:
>
>   root at lamprologus:~# cat /etc/pve/qemu-server/100.conf | grep vm-100-disk-19
>   scsi20: rpool-data:vm-100-disk-19,backup=0,discard=on,replicate=0,size=2000G
>
> but:
>
>   root at lamprologus:~# zfs list rpool-data/vm-100-disk-19
>   NAME                        USED  AVAIL  REFER  MOUNTPOINT
>   rpool-data/vm-100-disk-19  3.40T  3.84T  3.40T  -
>
> why 'USED' is 3.40T?
>
>
> Thanks.
>