zfs and snapshots.... again.

Foose

New Member
Aug 8, 2023
5
0
1
Again!

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.
disks-zfs.jpg

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

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

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

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

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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.
 
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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.
 
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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.
 

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