Install and configure Proxmox Backup Server

Set up a professional backup solution with deduplication, compression and integrity verification for your Proxmox VMs. PBS reduces storage space by 80% and drastically speeds up incremental backups.

Introduction

Proxmox Backup Server (PBS) is the official backup tool for Proxmox VE. Its advantages over the classic built-in backup (vzdump):

• Deduplication: identical blocks between backups are stored only once
• Incremental: only modified blocks since the last backup are transferred
• Client-side encryption: data leaves the PVE node already encrypted
• Integrity verification: SHA-256 checksum on all blocks
• Granular restore: recover a single file from a VM without restoring everything

Prerequisites

• A dedicated server or dedicated VM for PBS (separate from Proxmox VE)
• Minimum 4 GB RAM and 500 GB disk for the datastore
• Performant network between PBS and PVE (1 Gbps minimum)
• Proxmox VE 7.x or 8.x already in place

Step 1: Install Proxmox Backup Server

Option A: Install from ISO (recommended)

Download the official PBS ISO: https://www.proxmox.com/en/downloads/proxmox-backup-server

Install it as a regular OS, bare-metal on your backup server.

Option B: Install on existing Debian

If you want to install PBS on an existing Debian 12:

echo "deb http://download.proxmox.com/debian/pbs bookworm pbs-no-subscription" > /etc/apt/sources.list.d/pbs.list
wget https://enterprise.proxmox.com/debian/proxmox-release-bookworm.gpg -O /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg

apt update
apt full-upgrade -y
apt install -y proxmox-backup-server

Reboot:

systemctl reboot

Step 2: Access the web interface

Open your browser:

https://PBS_IP:8007

Log in with:

• User: root@pam
• Password: root password

Step 3: Create a datastore

The datastore is where backups are stored. On PBS, prefer using a ZFS pool or hardware RAID.

Prepare a ZFS pool for the datastore

# List available disks
lsblk

# Create a ZFS pool in RAIDZ1 on 3 disks
zpool create -f backup raidz1 /dev/sdb /dev/sdc /dev/sdd

# Optimizations
zfs set compression=lz4 backup
zfs set atime=off backup
zfs set xattr=sa backup
zfs set recordsize=1M backup

In PBS interface: Datastore → Add Datastore

• Name: pbs-store
• Backing Path: /backup
• GC Schedule: daily
• Prune Schedule: daily

Click Add.

Step 4: Create a dedicated user for Proxmox VE

Don't reuse the root account for backups. Create a dedicated user with limited permissions.

Configuration → Access Control → Add User:

• User name: pve-backup
• Realm: pbs
• Password: choose a strong one
• Enable: checked

Configuration → Access Control → Add Permission:

• Path: /datastore/pbs-store
• User: pve-backup@pbs
• Role: DatastoreBackup

Step 5: Get the PBS SSL fingerprint

On PBS:

proxmox-backup-manager cert info | grep -i fingerprint

Copy the Fingerprint (sha256): line.

Step 6: Add PBS as storage in Proxmox VE

On the PVE interface: Datacenter → Storage → Add → Proxmox Backup Server

• ID: pbs
• Server: PBS IP or hostname
• Username: pve-backup@pbs
• Password: the password created
• Datastore: pbs-store
• Fingerprint: paste the sha256 retrieved

Click Add. PVE verifies the connection.

Step 7: Schedule backups

Datacenter → Backup → Add:

• Storage: pbs
• Schedule: 02:00 (every day at 2 AM)
• Selection mode: All
• Compression: ZSTD (fast and good)
• Mode: Snapshot (no interruption)
• Mail Notification: Always (recommended)

Run a first manual backup to test:

VM → Backup → Backup Now → pbs.

Step 8: Configure retention (Prune)

Datastore → pbs-store → Prune Jobs → Add:

Recommended retention policy:

• Keep Last: 3 (last 3 backups)
• Keep Daily: 7 (last 7 days)
• Keep Weekly: 4 (last 4 weeks)
• Keep Monthly: 6 (last 6 months)
• Keep Yearly: 2 (last 2 years)

With deduplication, keeping 6 months of backups costs less space than you think.

Step 9: Enable Garbage Collection

GC cleans orphan blocks after prune operations.

Datastore → pbs-store → Maintenance → GC Schedule:

sat 04:00

Every Saturday at 4 AM.

Step 10: Automatic verifications

PBS can periodically verify backup integrity:

Datastore → pbs-store → Verify Jobs → Add:

• Schedule: sun 05:00
• Outdated After: 30 (re-verify backups every 30 days)

Step 11: Restore a VM

On PVE: VM → Backup → select backup → Restore.

Options:

• Storage: where to restore the disk
• VM ID: 100 (default) or new ID if you want to clone
• Start After: checked if you want to start immediately

To restore a single file from a Linux VM:

Backup → File Restore → browse → Download.

Troubleshooting

"fingerprint mismatch"

SSL fingerprint changed (certificate renewal). Get the new one:

proxmox-backup-manager cert info | grep -i fingerprint

Then update in PVE: Datacenter → Storage → pbs → Edit → Fingerprint.

First backup is slow

Normal: the first backup transfers 100% of data. Subsequent ones only transfer modified blocks (usually 1-5% of total).

Disk space doesn't decrease after prune

Prune marks blocks as orphans, but Garbage Collection actually deletes them. Run it manually:

proxmox-backup-manager garbage-collection start pbs-store

Integrity verification fails

Corrupted block on disk. Inspect:

proxmox-backup-manager verify pbs-store --outdated-after 0

If multiple backups are corrupted, check RAID/ZFS health:

zpool status backup

Useful commands

# Datastore status
proxmox-backup-manager datastore list

# Detailed status
proxmox-backup-manager datastore status pbs-store

# Manually run GC
proxmox-backup-manager garbage-collection start pbs-store

# Verify integrity
proxmox-backup-manager verify pbs-store

# List users
proxmox-backup-manager user list

# Update PBS
apt update && apt full-upgrade -y

# Backup logs
journalctl -u proxmox-backup-proxy -f

Conclusion

PBS transforms backup strategy for a Proxmox infrastructure. On a 20-VM fleet, commonly observed:

• Daily full backups in 10-15 minutes (vs 2-3h with vzdump)
• 80% disk space reduction thanks to deduplication
• Granular file restore in seconds

Going further:

• Configure a Remote Sync between two distant PBS for geographic resilience
• Enable client-side encryption for sensitive data
• Integrate PBS with S3 object storage (via remote sync to another PBS on S3 storage)

Resources

• Official documentation: https://pbs.proxmox.com/docs/
• ISO download: https://www.proxmox.com/en/downloads/proxmox-backup-server
• PBS forum: https://forum.proxmox.com/forums/proxmox-backup-server.74/