zfs and snapshots.... again.


New Member
Aug 8, 2023

I've read many posts and have thus far not been able to figure this out. I'm migrating from esxi to proxmox so I've got a learning curve.

First, I created a zfs storage tank.

Then, I added directories. ‘zfs create /tank/vms’ …

I can take snapshots on vm’s only using qcow2 format. I though qcow2 was not necessary on zfs?

I created a debian container in a zfs directory. I cannot do snapshots. No option to create the disk in qcow2 format.

Any of you 'sme's out their care to set me straight? My thanks.


  • storage.jpg
    43.5 KB · Views: 3
  • root-disk-raw.jpg
    15 KB · Views: 1
I can take snapshots on vm’s only using qcow2 format. I though qcow2 was not necessary on zfs?
When using a "Directory" storage PVE can'T make use of any features of the underlaying storage. So things like ZFS or LVM native snapshots won't work. If you want that you need to use a "ZFS" storage and point that to your ZFS dataset. Then you will use ZFS native blockdevices as virtual disks (zvols) and not image files. ZFS can only snapshot whole datasets or whole zvols, not single files, like your disk images.
Only option to use snapshots with a directory storage is to use qcow2 format, as then the snapshots will be taken on the file level within the qcow2 image instead of being done on the lower ZFS levels.
Last edited:
So even though the directories were created in zfs, they are still file based. How then do you create a zfs dataset? rtfm I guess. Thanks my friend.
zfs create somePool/NewDataset and then in the webUI: Datacenter -> Storage -> Add -> ZFS.
Make sure to increase the block size in case you are using a raidz1/2/3 and to tick the "thin" checkbox in case you want thin-provisioning.
Last edited:
Fantastic... it works. Thank you! Now I guess it doesn't make sense to move my .qcow2 vm's to zfs storage since the disk is not raw an cannot take advantage of the speed boost.
You can use the webUI to move virtual disks between storages. PVE will then covert them from qcow2 images to raw zvols.
So the move also converts. You've been very helpful. Thanks for sharing your knowledge.


The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!