Proxmox VE Backup System

Backups are essential for any robust IT deployment, and Proxmox Virtual Environment provides a fully integrated solution that leverages the capabilities of each storage type and guest system. This enables system administrators to fine-tune the balance between backup consistency and guest system downtime using the mode option.

Proxmox VE backups are always full backups, including the VM or CT configuration and all associated data. Backups can be initiated via the GUI or using the vzdump command-line tool.

Prerequisites

Backup Storage

Before a backup can run, a backup storage must be defined. Refer to the storage documentation for instructions on adding a storage. This can be either: - Proxmox Backup Server storage, where backups are stored as de-duplicated chunks and metadata. - File-level storage, where backups are stored as regular files.

Using a Proxmox Backup Server, ideally on a dedicated host, is recommended for its advanced features. Using an NFS server is a good alternative. In both cases,consider saving the backups later to a tape drive for off-site archiving.

Scheduled Backups

Backup jobs can be scheduled to run automatically on specific days and times for selected nodes and guest systems. See the Backup Jobs section for details.

Backup Modes For VMs

Stop Mode

This mode provides the highest backup consistency but requires a short downtime in the VM operation. It works by executing an orderly shutdown of the VM, and then running a background QEMU process to back up the VM data. After the backup is started, the VM resumes full operation if it was previously running. Consistency is guaranteed by using the live backup feature.

Suspend Mode

This mode is mainly provided for compatibility reason. It suspends the VM before calling the snapshot mode. Since suspending the VM results in longer downtime without significantly improving data consistency, using snapshot mode is recommended instead.

Snapshot Mode

This mode provides the lowest operation downtime, with a slight risk of inconsistency. It performs a Proxmox VE live backup, copying data blocks while the VM is running. If the guest agent is enabled (agent: 1) and running, it calls guest-fsfreeze-freeze and guest-fsfreeze-thaw to improve consistency.

Configuration Details

Backup Jobs

The backup jobs run automatically for all nodes Monday through Friday at 11 p. m. and Sundays at 1 a. m.

Backup Retention

Backup retention defines how many backups of different intervals are kept before older ones are automatically removed. Older backups will be pruned automatically. The following settings apply:

• Daily Backups: The system retains the last 3 daily backups.
• Weekly Backups: The system retains the last 2 weekly backups.
• Monthly Backups: The system retains the last 1 monthly backup.

Changelog

Date	Author	Message
2026-02-25	aresnikowa	Merge remote-tracking branch 'origin/master'