You will be amused with zfs performance in proxmox due to all the tuning that is possible. If this is going to be an existing zfs pool keep in mind it’s easier to just install proxmox with the zfs option and let it create a zfs rpool during setup. For the rpool tweak a couple options. Make sure ashift is at least 12 during the install or 13 if you are using some crazy fast SSD as proxdisk for the rpool.
It needs to be 12 if it’s a modern day spinner and probably a good setting for most ssds. Do not go over 12 if it’s a spinning disk.
Now beyond that you can directly import your existing zfs pool into proxmox with a single import command. Assuming you have an existing zfs pool.
In this scenario zfs would be fully maintaining disk operations for both an rpool and a media pool.
You should consider tweaking a couple things to really improve performance via the guide de I linked.
Proxmox vms/zvols live in their own dataset. Before you start getting to crazy creating vms make sure you are taking advantage of all the performance tweaks you can. By default proxmox sets a default record size for all datasets to 128k. qcow2, raw, and even zvols will benefit from record size of 64k because it tends to improve the underlying filesystem performance of things like ext4, XFS, even UFS. Imo it’s silly to create vm filesystems like btrfs if you’re vm is sitting on top of a cow filesystem.
Another huge improvement is tweaking the compression algorithm. lz4 is blazing fast and should be your default go to for zfs. The new one is pretty good but can slow things down a bit for active operations like active vm disks. So make sure your default compression is lz4 for datasets with vm disks. Honestly it’s just a good default to specify for the entire pool. You can select other compressions for datasets with more static data.
If you have a media dataset full of files like music, vids, pics. Setting a record size of 1mb will heavily improve disk io operations.
In proxmox it will default to grabbing half of your memory for arc. Make sure you change that after install. It’s a file that defines arc_max in byte number format. Set the max to something more reasonable if you have 64 gigs of memory. You can also define the arc_min
Some other huge improvements? If you are using an SSD for your proxmox install I highly recommend you install log2ram on your hypervisor. It will stop all those constant log writes on your SSD. It will also sync them to disk on a timer and shutdown/reboot. It’s also a huge performance and SSD lifespan improvement to migrate /tmp and /var/tmp to tmpfs
So many knobs to turn. I hope you have fun playing with this.