There was a recent conversation on the Practical ZFS discourse site about poor disk performance in Proxmox (https://discourse.practicalzfs.com/t/hard-drives-in-zfs-pool-constantly-seeking-every-second/1421/). Not sure if you’re seeing the same thing, but it could be that your VMs are running into the same too-small volblocksize
that PVE uses to make zvols for its Vans under ZFS.
If that’s the case, the solution is pretty easy. In your PVE datacenter view, go to storage and create a new ZFS storage pool. Point it to the same zpool/dataset as the one you’ve already got and set the block size to something like 32k or 64k. Once you’ve done that, move the VM’s disk to that new storage pool.
Like I said, not sure if you’re seeing the same issue, but it’s a simple thing to try.
If you want an image, it doesn’t matter what the underlying file system is. You should be able to use a tool like Clonezilla and get a 1:1 copy. Depending how you’ve set up partitioning, you could also use
sgdisk
to set up the proper partitions andzfs send/recv
for the new data portion of the drive and install a boot loader. That’s probably the way I’d go in this instance.