Deduplicated Proxmox backups with Proxmox Backup Server and ZFS

Overview There are many ways to back up your Proxmox virtual machines. One of the most popular ways to do so is via Proxmox Backup Server, which gives you many advantages: Deduplication of common data. The ability to cherry pick files out of your backups. Tight integration with the Proxmox ecosystem. However, how is one to achieve proper 3-2-1 backups using this mechanism? One way is to run multiple datastores, some local and some using Amazon S3 compatible endpoints. ...

April 22, 2026 · 2 min

Issues transferring Windows 11 VM from KVM to Proxmox

I ran into a strange issue when trying to transfer a Windows 11 Pro virtual machine from KVM on my Fedora desktop to Proxmox. The VM was using a VirtIO block device for it’s storage as I normally do. I transferred the VM qcow2 file to Proxmox and created a new VM with matching hardware, the imported the disk with: qm importdisk 300 win11.qcow2 fast (fast being the name of my SSD zpool.) ...

February 20, 2026 · 2 min

Passing through Intel Arc A380 to a Proxmox VM

I recently purchased an AsRock Challenger ITX Intel Arc A380 GPU to use for my video transcoding needs. It was a bit of a headache to get it passed through to a VM in Proxmox, so here’s a log of what worked for me, in hopes that it will help someone else down the road. My VM is Ubuntu 24.04 LTS, running kernel 6.14 (HWE kernel). Proxmox is version 8.4. ...

August 17, 2025 · 4 min

Proxmox Setup Notes

Proxmox installation steps Overview This post is a reference for me and anyone else that finds it useful. I’ve never bothered documenting this before, which leads me to missing stuff every time I set up a new box. This post will continue to be updated if I add anything new. Installation The primary thing to get right here is the storage configuration. Even if it’s a single disk I will typically do ZFS. Click on Options. Choose whichever ZFS topology you want. Click on Advanced Options. Change Compression from “on” to “lz4”. This is the default anyway, but I like to be sure. ashift should be set to 12 or 13. I typically do 12, as this targets 4k physical sectors. Make sure that you have the correct disks selected. Any disk you do not want to be part of the boot pool should be set to “do not use”. For the rest of the setup you can pretty much just click Next Next Next. I do recommend setting the correct time zone and a good DNS server. Post-Install If you don’t have an Enterprise subscription we need to disable the enterprise repository and enable the one for no-subscription. Click on the individual node (not Datacenter) and go to Updates > Repositories. Click on Add and select No Subscription from the dropdown. Next, select the repositories labeled “Enterprise” and disable them. Enable Debian Non-Free-Firmware repository. This one can’t be done through the GUI. SSH in or use the web shell. Edit the sources vim /etc/apt/sources.list.d/pve-no-enterprise.list` Add the following repo, replacing $VERSION with your release’s Debian base (bookworm, trixie): https://deb.debian.org/debian $VERSION main non-free-firmware Install the firmware microcode for your hardware vendor Run apt update apt install intel-microcode OR apt install amd64-microcode At this point, update the system. Reboot if needed. Next, lets fix the ZFS configuration. Click on the Datacenter tab and go do down to Storage. Select your zpool (or pools) and click Edit. You will have to do this for every pool individually. Enable thin provisioning. Change the Block Size to 64k or 128k. Either is probably fine, but the default 16k is abysmal for VM disks. This setting is the zvol equivalent to the recordsize property on datasets. Having this not match your workload will usually result in massive write amplification. This is why ZFS got a reputation for quickly killing SSDs, but it doesn’t have to if you configure your pool correctly. Click on the individual node again. Go to System > Network and select any bridges that you’ve created. Set them to be VLAN-aware. Set up the notification system under Datacenter > Notifications. I will typically have it send me only backup failure notices and warnings about things like failed disks. I will typically set up a VM template at this stage to save myself a bunch of work later. See links below for options. Other Notes If you’re trying to set up a new ZFS storage pool and the disks aren’t showing up in the interface - the Proxmox interface will not show you any disks that have partitions on them. ...

August 7, 2025 · 4 min