Proxmox VE 9.0: Debian 13, LVM Snapshots and SDN Fabrics

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Proxmox Server Solutions released Proxmox VE 9.0 on 5 August 2025. The new major release is based on Debian 13 “Trixie”. This post summarises the main changes based on the press release and the official release notes.

Snapshots on shared LVM storage

Many environments moving from VMware connect their servers to a SAN over iSCSI or Fibre Channel. In Proxmox VE this storage usually holds a thick-provisioned LVM volume group, which could not take snapshots until now. Version 9.0 stores snapshots as volume chains. This works on thick LVM and on directory, NFS and CIFS storage. The feature is a technology preview, so test it before you rely on it in production.

SDN fabrics

The SDN stack now supports fabrics. You can set up routing between cluster nodes with OpenFabric or OSPF in the web interface. This helps with full-mesh networks for Ceph and with networks that have several paths between nodes.

High availability with affinity rules

High availability (HA) now has affinity rules. You can keep certain VMs together on one node, or make sure they always run on different nodes. After a failure, two domain controllers or two database nodes no longer end up on the same server.

Other changes

  • ZFS: You can add disks to existing RAIDZ pools.
  • Mobile interface: The smartphone view was rebuilt with the Rust toolkit Yew.
  • Networking: A dedicated network for storage replication can be set at datacenter level. The tool proxmox-network-interface-pinning ties network interface names to their MAC address.
  • Firewall: An nftables-based firewall is available as an opt-in technology preview.

Component versions

Base
Debian 13 “Trixie”
Kernel
Linux 6.14 (default)
QEMU
10.0.2
LXC
6.0.4
ZFS
2.3.3
Ceph
Squid 19.2

Before you upgrade

You can upgrade directly from Proxmox VE 8.4. Run the pve8to9 checker first and follow the guide in the Proxmox wiki. Pay particular attention to these points:

  • Interface names: The new kernel may name network interfaces differently. Check /etc/network/interfaces afterwards, or the node may become unreachable.
  • MTU: VirtIO network devices without an explicit MTU now inherit the bridge MTU. Previously they defaulted to 1500.
  • cgroup v1: Proxmox VE 9 supports cgroup v2 only. Containers with very old operating systems may no longer start.
  • GlusterFS: Support has been removed. Move your VMs to other storage first.
  • Permissions: The VM.Monitor privilege is gone. Adjust any custom roles.

Planning the upgrade to version 9 and would rather not do it alone? We review your cluster beforehand and carry out the upgrade with you.

Where things stand today

This post describes the situation in August 2025. As of November 2026 the current version is Proxmox VE 9.2. According to the Proxmox VE FAQ, Proxmox VE 8 reached end of support in August 2026.

Read more on our Proxmox VE page.