Date: 2022-11-29
So you’d like to shrink the ZFS volume used as a VM disk. It isn’t too hard, but we have to shrink the VM’s partition before shrinking the ZFS volume itself. Be sure to have snapshots/backups of all volumes used by this VM. You might screw them up!
export zvol=jankenpool/e/vm-106-disk-0
export desired_GiB=64
Assuming this volume is a VM’s disk, boot that VM with a GParted livecd. Resize the partition there. Make it maybe 1 MiB less than you want, just in case.
zfs set volsize=${desired_GiB}G ${zvol}
qm rescan
#^ Update Proxmox's view of reality.
#> Reparation in the VM first! I like using the GParted livecd.
zfs set volsize=400G jankenpool/e/vm-106-disk-0
qm rescan