Proxmox Backup Server PBS install and configure VM CT backup

Proxmox Backup Server (PBS) is an open-source enterprise backup solution designed specifically for Proxmox VE environments. It features Incremental Backup with Changed Block Tracking, chunk-based Deduplication, and client-side AES-256 Encryption — making it far more efficient than traditional full backups.

PBS vs. PVE Built-in Backup: Key Differences

FeaturePVE BackupProxmox PBS
Incremental Backup❌✅ Changed Block Tracking
Deduplication❌✅ Save 60-80% storage
Encryption (AES-256)❌✅ Client-side
Backup Verification❌✅ Automatic integrity check
Flexible RetentionLimited✅ Daily/Weekly/Monthly
Web UIVia PVE✅ Dedicated UI

System Requirements

💡 Best Practice: Install PBS on a separate machine or different datacenter from your PVE nodes to avoid a single point of failure.

Installing Proxmox Backup Server on Debian 12

Step 1: Add PBS Repository

echo "deb http://download.proxmox.com/debian/pbs bookworm pbs-no-subscription" \
  > /etc/apt/sources.list.d/pbs-no-subscription.list

wget -qO- https://enterprise.proxmox.com/debian/proxmox-release-bookworm.gpg \
  | gpg --dearmor > /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg

apt update

Step 2: Install PBS

apt install -y proxmox-backup-server

After installation, PBS starts automatically. Access the Web UI at https://<PBS-IP>:8007

Step 3: Create a Datastore

mkdir -p /backup

# Create datastore via CLI
proxmox-backup-manager datastore create main /backup

Connecting PBS to Proxmox VE

Add PBS Storage on PVE

In PVE Web UI: Datacenter → Storage → Add → Proxmox Backup Server

Get PBS Fingerprint

proxmox-backup-manager cert info | grep "Fingerprint"

Creating Backup Jobs

PVE Web UI: Datacenter → Backup → Add → Select PBS storage, choose VMs/CTs, set schedule and Retention Policy.

Retention Policy Examples

ParameterExampleMeaning
keep-last3Keep 3 most recent backups
keep-daily7Keep 1 backup per day for 7 days
keep-weekly4Keep 1 backup per week for 4 weeks
keep-monthly3Keep 1 backup per month for 3 months

Enabling Encryption

proxmox-backup-client key create /etc/pve/priv/backup-encryption.key

⚠️ Critical: Store your encryption key in a separate, secure location. Without it, restoring encrypted backups is impossible.

Restoring from PBS

Restore via CLI

# Restore VM 100 to VM 200
qmrestore pbs-main:backup/vm/100/2026-09-11T00:00:00Z 200 --start

# Restore CT 101 to CT 201
pct restore 201 pbs-main:backup/ct/101/2026-09-11T00:00:00Z

Maintenance: Pruning and Garbage Collection

# Prune old backups per retention policy
proxmox-backup-manager prune-job create prune-daily \
  --datastore main \
  --keep-last 3 --keep-daily 7 --keep-weekly 4 --keep-monthly 3 \
  --schedule "02:00"

# Reclaim space from unreferenced chunks
proxmox-backup-manager garbage-collection start main

Troubleshooting

Backup Slow or Timing Out

Service Status

systemctl status proxmox-backup.service
journalctl -u proxmox-backup.service -n 50
ss -tlnp | grep 8007
Is PBS free to use?
Yes. PBS has a Community Edition via the no-subscription repository with full features. Enterprise subscription adds priority support and stable updates.
Can PBS run on the same host as PVE?
Yes, but not recommended. If the host fails, you lose both PVE and PBS. A separate machine or location is strongly advised.
Does PBS support both VMs and Containers?
Yes — QEMU VMs and LXC Containers both supported. For VMs, the QEMU Guest Agent enables live backup without shutdown.
How does Deduplication work?
PBS splits data into 4MB chunks and stores only unique chunks by hash. Identical chunks across VMs or backup generations are stored only once, saving 60-80% storage on typical workloads.
Can I sync backups to a remote PBS?
Yes. PBS Sync Jobs replicate backup data to a remote PBS instance, enabling off-site disaster recovery.