ZFS: REFRESERVATION - correct way to enable?

[alet]

I have installed a 2 node cluster proxmox 6.3.
During installation i choose a mirror zfs installation.
no i have the following rpool created by defaulte proxmox installer

NAME          SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
rpool         888G  90.2G   798G        -         -     0%    10%  1.00x    ONLINE  -

I mounted /var/lib/vz as storage folder via GUI.

i have restore some VM from old 3.0 proxmox backups into the folder type storage.
But the occupied space does not match. I discovered that the zfs storage is in thin provisioning mode by default in fact:

rpool             refreservation  none       default
rpool/ROOT        refreservation  none       default
rpool/ROOT/pve-1  refreservation  none       default
rpool/data        refreservation  none       default

Now i would know how to disable thin provisioning and enable thick provisioning

i tried from the promxox GUI to disable thin provision by unticking the thin provision option on the storage "LOCAL" bu nothing changed.

Any help?

 

[leesteken]

Looks like it only affects new disks.

 

[alet]

Looks like it only affects new disks.

Thank you for the answer.
It seems correct to me that it affect only the new disk the passage from thick to thin (it cannot reduce the size).
But how to make the reverse? Going from Thin to thick? I can always make a dump e restore them again into new machine. The issue is that it seems setting the checkbox into DISABLING THIN (i want to ENABLE THICK) it doesn't affect the new VM.