Learn Proxmox Backup Server - Physical Host & Container Backup

#Introduction

So far we have backed up VMs and CTs through PVE — but there are many machines that do not live in Proxmox: physical servers, VPSes, or workstations that still must be protected. Episode 11 introduces proxmox-backup-client as the universal tool for file backups from any host, plus confirms that LXC containers can be backed up and restored just like VMs.

Imagine PBS like a document courier service: if VMs are customers with a regular contract (PVE integration), proxmox-backup-client is a one-way shipment package from anyone — as long as you know the warehouse address (repository), anyone can send.

#Backing Up Physical Hosts with proxmox-backup-client

#PXAR: The Proxmox Archive Format

When backing up files, proxmox-backup-client packages the data in PXAR (Proxmox Archiver) format — an archive format designed specifically for PBS that supports full file metadata, sparse handling, and seamless integration with dedup chunking. PXAR archives are stored as named archives inside a snapshot, e.g. etc.pxar, data.pxar.

#Snapshot Structure for File Backups

Host snapshot anatomy

host/web01/2026-08-12T22:15:01Z
├── etc.pxar      → /etc archive
└── data.pxar     → /srv/data archive

Each archive gets a unique name. On restore, you choose which archive you need — not necessarily all of them.

#Basic Commands

Backup directly from a physical host (without PVE) using a PBS user and repository:

Back up physical host directories

proxmox-backup-client backup \
  etc.pxar:/etc \
  data.pxar:/srv/data \
  --repository backup@pbs@10.0.1.10:store1 \
  --keyfile /etc/proxmox-backup/enc.key

etc.pxar:/etc means "an archive named etc.pxar containing the folder /etc". For raw partitions/disks, proxmox-backup-client supports block device backups (e.g. root.pxar from /dev/sda) with appropriate options — but for hosts, file backup is usually sufficient and more efficient.

Tip

Use a namespace to group host backups so they do not mix with PVE VMs: --ns host-bare-metal. Namespaces keep the datastore tidy when there are many different backup sources — also useful for multi-tenancy in episode 12.

#Restoring Files from a Host

To get data back:

Restore the etc.pxar archive to a local folder

proxmox-backup-client restore \
  --repository backup@pbs@10.0.1.10:store1 \
  --keyfile /etc/proxmox-backup/enc.key \
  host/web01/2026-08-12T22:15:01Z etc.pxar /mnt/restored

etc.pxar /mnt/restored extracts the archive to /mnt/restored. Restoring to a new system after a server fails is the main scenario — install a fresh Debian, install proxmox-backup-client, then restore the configuration from the archive.

#Automating Host Backups

Install proxmox-backup-client on the physical host, then schedule via cron/systemd timer:

Daily cron for host backup

0 2 * * * root proxmox-backup-client backup etc.pxar:/etc data.pxar:/srv/data \
  --repository backup@pbs@10.0.1.10:store1 --keyfile /etc/proxmox-backup/enc.key

#Backing Up LXC Containers

#CTs Are Backed Up Like VMs

Proxmox VE treats LXC containers (CTs) as equal to VMs when it comes to backup: open CT → Backup, choose the pbs1 storage, and run it. Behind the scenes, vzdump reads the container's entire filesystem and sends it to PBS as a ct-type snapshot.

Manual backup of CT 300 to pbs1

vzdump 300 --storage pbs1 --mode snapshot

CT backups also support guest agent hooks, but because LXC shares the host kernel, CT snapshot backups are generally lighter than full VMs.

#Restoring to a New CT

Restoring a CT from PBS: CT → Backup → select snapshot → Restore. Choose a new CT ID (e.g. 301) if 300 is still active, choose a target storage, and the container is rebuilt from the snapshot. The entire container configuration (network, mounts, resources) is restored along with it.

Check CT snapshots in PBS

proxmox-backup-client snapshot list \
  --repository backup@pbs@10.0.1.10:store1

ct/300/...-type snapshots will appear. Verify the restore result by starting the restored CT and checking the services inside.

Warning

Do not back up a CT by copying the /var/lib/lxc folder or manually backing up container files while the container is running — the result is inconsistent. Always use the PVE backup (vzdump), which understands container snapshots correctly.

#Closing

Key takeaways:

proxmox-backup-client backs up any host's files/partitions directly to a PBS datastore.
The PXAR format stores named archives (e.g. etc.pxar:/etc) within a single snapshot.
Host restore: reinstall the system, install the client, then proxmox-backup-client restore.
Automate physical hosts via cron/systemd timer with --repository and --keyfile.
LXC is backed up via PVE (vzdump) just like VMs, with ct-type snapshots.
Restore a CT to a new CT via the GUI, then verify by starting the restored result.

In the next episode, episode 12, we will manage who can do what: ACL, user & remote access — creating per-tenant users, installing per-datastore ACLs (Backup/Read/Write), creating API tokens, and securing remote access with HTTPS without opening unnecessary SSH. A secure multi-tenant PBS starts here!