Proxmox Incremental Backup Jun 2026

| Traditional Backup | Proxmox + PBS Incremental | |-------------------|----------------------------| | Full backup daily = huge storage | Only unique chunks stored once | | Slow backup windows | Fast, often <5 min for small changes | | High network load | Minimal data transfer | | Deduplication only after backup | Inline, real-time deduplication | | Restore requires merging increments | Restore any snapshot directly as full |

Proxmox VE's built-in backup feature allows you to create incremental backups of your VMs and containers. Here's a high-level overview of the process:

Out of the box, Proxmox VE supports vzdump , which creates consistent snapshots. However, standard vzdump to NFS, CIFS, or local storage is not truly incremental. It supports dirty-bitmap for QEMU (since Proxmox 6.4), but this is limited. Standard vzdump simply compresses and stores full copies. This is slow and wasteful. proxmox incremental backup

: PBS breaks data into "chunks". For virtual machines, it uses fixed-size chunks, while containers use variable-sized chunks to better handle file-level changes. If a chunk already exists on the server—whether from a previous backup of that VM or an entirely different one—the server simply records a reference to it rather than saving it again.

The dirty bitmap was lost. This happens if: | Traditional Backup | Proxmox + PBS Incremental

By implementing Proxmox Backup Server, you unlock:

: Once installed, log into the PBS web interface and create a where your backups will live. Fingerprint It supports dirty-bitmap for QEMU (since Proxmox 6

Proxmox itself doesn’t do incremental backups. But Proxmox VE + Proxmox Backup Server together create a true, efficient, incremental + deduplicated backup system – one that works at the block-chunk level, not the file level, making it fast, space-efficient, and reliable.

A "Datastore" is where the incremental chunks are stored. It must be a dedicated filesystem (ext4, XFS, or ZFS).

The initial backup is slightly slower due to chunking overhead (CPU). However, daily backups are 10x faster and use 99% less network bandwidth . Over 30 days, you save 14.4 TB of storage.

The fear with incremental backups is always restore complexity: "Do I need the last full plus all 30 incrementals to restore?"