Proxmox Backup Server: install your own, or use one without installing anything

What is Proxmox Backup Server?

PBS is free software (AGPLv3 license), with no limit on storage or number of clients. It receives backups from Proxmox VE (VMs and containers) and from proxmox-backup-client (Linux servers), and stores them in a datastore: a directory on an ext4, xfs or ZFS filesystem, or S3 object storage.

• Incremental: only changed data is sent, yet every backup is still a full backup, since it references all its data.
• Deduplication: data is split into chunks (typically 4 MiB for a VM). An identical chunk is stored once, even across different machines. Scope, effect of encryption and the displayed factor: deduplication in Proxmox Backup Server.
• Verification: verify jobs read the chunks back and check their integrity.
• Fine-grained restore: a whole VM, or a single file, from Proxmox VE (File Restore button) or from the command line.
• Encryption: client-side AES-256-GCM, optional. It is not enabled by default; you turn it on.

PBS or regular vzdump backups?

Install Proxmox Backup Server 4.2 step by step

Nine steps, from choosing the machine to the first restore. Commands run as root on the PBS server, except those marked "Proxmox VE".

1. Size the server

Run PBS on a machine separate from your hypervisors: if the hypervisor fails, the backups stay reachable. On HDDs, the special device makes the difference for garbage collection and verification, which walk through millions of files. It is declared when the pool is created, on SSDs, with the same redundancy as the pool:

zpool create -f -o ashift=12 backup mirror /dev/sdb /dev/sdc special mirror /dev/nvme0n1 /dev/nvme1n1

Careful: a special device added to a pool cannot be removed. For the pool's usable capacity and the space to plan for the datastore, see the ZFS RAIDZ capacity and PBS storage calculator. To estimate how long a full backup takes for your volume and bandwidth, use our backup window calculator.

2. Install from the ISO

1. Download the proxmox-backup-server_4.2-1.iso image from proxmox.com/downloads and write it to a USB stick.
2. Boot the server from it and follow the installer. Filesystem: ext4 by default, xfs or ZFS. No ZFS on top of hardware RAID.
3. Once the server has rebooted, open https://server-address:8007 and log in as root, realm "Linux PAM".

3. Or install on Debian 13 (trixie)

On an existing Debian 13, add the Proxmox repository key and check its hash:

wget https://enterprise.proxmox.com/debian/proxmox-archive-keyring-trixie.gpg \
  -O /usr/share/keyrings/proxmox-archive-keyring.gpg
sha256sum /usr/share/keyrings/proxmox-archive-keyring.gpg
# expected: 136673be77aba35dcce385b28737689ad64fd785a797e57897589aed08db6e45

Then declare the repository, here the no-subscription one, in /etc/apt/sources.list.d/proxmox.sources:

Types: deb
URIs: http://download.proxmox.com/debian/pbs
Suites: trixie
Components: pbs-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg

And install:

apt update
apt install proxmox-backup-server   # keeps the Debian kernel, minimal install
# or
apt install proxmox-backup          # same set as the ISO, Proxmox kernel with ZFS

Proxmox intends the pbs-no-subscription repository for testing and non-production use. In production, a subscription gives access to the pbs-enterprise repository.

4. Create a datastore

In the web interface: Add Datastore, in the side menu, Datastore section. From the command line, for example with a two-disk ZFS mirror:

proxmox-backup-manager disk zpool create zpool1 --devices sdb,sdc --raidlevel mirror
proxmox-backup-manager datastore create store1 /mnt/datastore/zpool1

Two variants exist. A removable datastore (since PBS 3.3) lives on a disk you mount and unmount, which is handy for an offline copy. An S3 datastore uses S3-compatible object storage with a local cache; it has been officially supported since PBS 4.2.

5. Create a user and a token for Proxmox VE

Don't use root@pam in Proxmox VE. Create a dedicated user, an API token, and give the DatastoreBackup role on the datastore to both the user and the token:

proxmox-backup-manager user create pve@pbs
proxmox-backup-manager user generate-token pve@pbs pve1
proxmox-backup-manager acl update /datastore/store1 DatastoreBackup --auth-id pve@pbs
proxmox-backup-manager acl update /datastore/store1 DatastoreBackup --auth-id 'pve@pbs!pve1'

The token secret is shown only once: write it down. A new token has no permissions at all, and it can never do more than its user: its permissions are intersected with the user's. Hence the two acl update lines. The quotes around pve@pbs!pve1 keep the shell from interpreting the exclamation mark.

6. Get the certificate fingerprint

At install time, PBS generates a self-signed certificate. Proxmox VE recognizes it by its fingerprint:

proxmox-backup-manager cert info | grep Fingerprint

In the web interface: Dashboard, then Show Fingerprint. With a Let's Encrypt (ACME) certificate, the fingerprint is no longer needed; the HTTP challenge requires the server's port 80 to be reachable from the internet.

7. Add the PBS to Proxmox VE

In Proxmox VE: Datacenter, Storage, Add, Proxmox Backup Server. Fill in the server, the datastore, the fingerprint, and as username the token ID (pve@pbs!pve1) with its secret as password. From the command line (Proxmox VE):

pvesm add pbs pbs-local --server 192.0.2.10 --datastore store1 \
  --username 'pve@pbs!pve1' --fingerprint 'AB:CD:...' --password

To encrypt backups client-side, add --encryption-key autogen: Proxmox VE generates a key, which you must back up elsewhere, or the backups become unrecoverable once the node is lost. Proxmox also points out that unencrypted backups are easier to recover: encrypt when backups leave your walls.

8. First backup, retention and maintenance

First backup of a VM from Proxmox VE (or through a scheduled job under Datacenter, Backup):

vzdump 100 --storage pbs-local

The second backup of the same VM only transfers changed chunks: that is where deduplication shows. On the PBS, three jobs then look after the datastore, scheduled in the Prune & GC tab and in Verify Jobs:

• Prune: applies retention (keep-last, keep-daily, keep-weekly, keep-monthly…). It removes backups from the list, not the data yet. The backup retention simulator (GFS) shows what your rules keep, day by day.
• Garbage collection: actually frees space. A chunk is only removed if it has not been used for at least 24 h 05; until then, it shows as "Pending removals". The documentation suggests starting with a weekly schedule.
• Verify: reads chunks back and checks their integrity. Proxmox recommends re-verifying all backups at least monthly.

proxmox-backup-manager prune-job create daily-prune --store store1 --schedule daily \
  --keep-daily 14 --keep-weekly 8 --keep-monthly 12
proxmox-backup-manager datastore update store1 --gc-schedule weekly
proxmox-backup-manager verify-job create monthly-verify --store store1 --schedule monthly \
  --ignore-verified true --outdated-after 30

9. Restore, down to a single file

From Proxmox VE, in the PBS storage, Backups tab: Restore for a whole VM, File Restore to browse the backup and pick a file. For a Linux server backed up with proxmox-backup-client:

export PBS_REPOSITORY='pve@pbs!pve1@192.0.2.10:store1'
export PBS_PASSWORD='token-secret'
proxmox-backup-client backup root.pxar:/
proxmox-backup-client snapshot list
proxmox-backup-client catalog shell host/srv01/2026-09-25T02:00:00Z root.pxar
proxmox-backup-client restore host/srv01/2026-09-25T02:00:00Z root.pxar /restore/

A backup you have never restored is still an assumption: run a test restore in the first week, then regularly. The client-side walkthrough is in our proxmox-backup-client on Linux guide.

Upgrade from PBS 3 to PBS 4

PBS 3 reached end of life in August 2026. Moving to PBS 4 (Debian 12 "bookworm" to Debian 13 "trixie") starts from an up-to-date 3.4, version 3.4.2-1 or newer, with 10 GB free on / and a copy of /etc/proxmox-backup:

proxmox-backup-manager versions          # must show 3.4.2-1 or newer
pbs3to4 --full                           # re-run it throughout the upgrade
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
# then rewrite the Proxmox repositories in .sources format (step 3)
apt update && apt dist-upgrade
systemctl reboot

After the reboot, check that proxmox-backup-proxy.service and proxmox-backup.service are running. Watch network interface names, which may change with the new kernel. The official guide: Upgrade from 3 to 4.

What about LTO tape?

PBS can write to tape: LTO-5 and later, LTO-4 on a best-effort basis. Tapes are grouped into media pools, filled by tape backup jobs, and a tape library robot can be driven directly. A restore goes back to disk first. This is what we operate in Magnetic PBS and AirGapped LTO PBS.

Take your PBS offsite: the missing copy

Your PBS is running. One weak spot remains: it sits in the same place as what it protects. A fire, a theft, or ransomware that reaches the server, and everything goes at once. The 3-2-1 rule (three copies, two media, one offsite) calls for a copy elsewhere, and the French ANSSI backup guide asks for one offline.

• Replicate to a remote PBS: a sync job copies backups, in pull mode (the remote PBS fetches) or push mode (since PBS 3.3, your PBS sends). Only missing chunks travel. PBS replication tutorial.
• Keep an offline copy: a ZFS pool sent with zfs send to disks that are then unplugged. Offline PBS copy with zfs send.
• Prepare for losing the server: reactivate a datastore on a new PBS, and migrate a PBS to a new machine.

For the remote copy, our hosted PBS can be the target: in push mode, your PBS sends to a datastore with us, using an account delivered without delete permission. An attacker who takes over your PBS therefore cannot wipe the remote copy, in the configuration delivered by default. There are limits: an administrator account you asked for, a breach on our side or a PBS flaw would allow deletion. That is why our offline plans exist.