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Automated Backups with Proxmox Backup Server

· 4 min read · 695 words
proxmox backup pbs homelab storage
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Contents

The Problem with Ad-hoc Backups

Proxmox VE has built-in backup functionality — you can snapshot a VM to a directory or NFS share on a schedule. But it stores full backups each time, space grows fast, and restoring requires the whole archive. Proxmox Backup Server (PBS) solves all three problems.

PBS is a dedicated backup server that:

  • Stores backups with client-side deduplication and compression (typically 50–80% space savings)
  • Does incremental backups — only changed chunks are uploaded
  • Supports instant verification by recalculating checksums
  • Has pruning policies — keep 7 daily, 4 weekly, 12 monthly backups automatically

Architecture

PBS is a separate Debian-based appliance. It does not run inside Proxmox VE. You have a few options:

  • Dedicated machine — ideal, but overkill for most homelabs
  • Second Proxmox node — run PBS as a VM on a different node from what it’s backing up
  • Same node VM — convenient, but you lose backups if the node dies

I run PBS as a VM on my second Proxmox node (pve-02), backing up VMs from both nodes. The backup storage is a 2 TB HDD passed through to the PBS VM.

Installing Proxmox Backup Server

Download the PBS ISO from the Proxmox downloads page. It installs like Proxmox VE — boot from USB, follow the wizard, give it a static IP.

The web UI runs on port 8007: https://pbs-ip:8007

Setting Up a Datastore

A datastore is where backups are stored. In the PBS UI:

  1. Go to Datastore -> Add Datastore
  2. Set a name (e.g., main-backup)
  3. Set the path to your backup disk (e.g., /mnt/backup-disk)
  4. Configure a Prune Schedule — I use: keep last 7 daily, 4 weekly, 3 monthly

PBS creates its chunk store structure in that directory automatically.

Adding PBS to Proxmox VE

In the Proxmox VE web UI:

  1. Datacenter -> Storage -> Add -> Proxmox Backup Server
  2. Enter the PBS server IP, port 8007, your PBS username/password
  3. Select the datastore
  4. Set a fingerprint (copy from PBS: Configuration -> Certificates -> Fingerprint)

The PBS storage now appears as a backup target on your Proxmox nodes.

Creating a Backup Job

In Proxmox VE:

  1. Datacenter -> Backup -> Add
  2. Choose your PBS storage
  3. Select VMs/containers to back up (or “all”)
  4. Set a schedule — I run nightly at 2 AM
  5. Set compression to zstd (best speed/ratio balance)
  6. Enable Send email on error if you have SMTP configured

The first backup is a full transfer. All subsequent backups only upload changed data chunks.

Monitoring Backup Jobs

In Proxmox VE, check Datacenter -> Backup -> Job History. In PBS, go to Datastore -> main-backup -> Content to see all stored backups with sizes and timestamps.

You can also verify backup integrity from PBS:

proxmox-backup-client verify <datastore> <backup-id>

Restoring a VM

From Proxmox VE, find the VM in the resource tree, go to Backup, select a restore point, and click Restore. You can restore to any node in the cluster and rename the VM.

For granular file-level restores, PBS mounts the backup as a FUSE filesystem:

proxmox-backup-client mount <datastore> <backup-id> /mnt/restore

Then browse and copy individual files.

Pruning and Retention

PBS prunes automatically according to your datastore schedule. You can also trigger a prune manually from the web UI or CLI:

proxmox-backup-manager prune --keep-daily 7 --keep-weekly 4 --keep-monthly 3 <datastore>

Pruning removes backup snapshots but the underlying chunks are only freed during garbage collection:

proxmox-backup-manager garbage-collection start <datastore>

Schedule weekly GC runs to keep disk usage accurate.

Offsite Replication

PBS supports remote sync — you can replicate a datastore to a second PBS instance at a different location (friend’s house, VPS). In the PBS UI: Sync Jobs -> Add.

This gives you offsite backups without needing a cloud service. Both endpoints deduplicate independently, so only unique chunks are transferred.

Storage Sizing

A rough formula: assume your VMs total X GB of used disk, expect 60% compression, and keep N snapshots with ~5% daily change rate:

Storage needed = X * 0.4 * (1 + N * 0.05)

For 500 GB of VMs with 30 snapshots: 500 * 0.4 * 2.5 = 500 GB of backup storage. Your actual results will vary depending on data type — highly compressible text/configs will do much better.