Introduction

What is Proxmox Backup Server?

Proxmox Backup Server is an enterprise-class, client-server backup solution that is capable of backing up virtual machines, containers, and physical hosts. It is specially optimized for the Proxmox Virtual Environment platform and allows you to back up your data securely, even between remote sites, providing easy management through a web-based user interface.

It supports deduplication, compression, and authenticated encryption (AE). Using Rust as the implementation language guarantees high performance, low resource usage, and a safe, high-quality codebase.

Proxmox Backup uses state of the art cryptography for both client-server communication and backup content encryption. All client-server communication uses TLS, and backup data can be encrypted on the client-side before sending, making it safer to back up data to targets that are not fully trusted.

Architecture

Proxmox Backup Server uses a client-server model. The server stores the backup data and provides an API to create and manage datastores. With the API, it's also possible to manage disks and other server-side resources.

The backup client uses this API to access the backed up data. You can use the proxmox-backup-client command-line tool to create and restore file backups. For QEMU and LXC within Proxmox Virtual Environment, we deliver an integrated client.

A single backup is allowed to contain several archives. For example, when you backup a virtual machine, each disk is stored as a separate archive inside that backup. The VM configuration itself is stored as an extra file. This way, it's easy to access and restore only the important parts of the backup, without the need to scan the whole backup.

Main Features

Support for Proxmox VE:

The Proxmox Virtual Environment is fully supported, and you can easily backup virtual machines and containers.

Performance:

The whole software stack is written in Rust, in order to provide high speed and memory efficiency.

Deduplication:

Periodic backups produce large amounts of duplicate data. The deduplication layer avoids redundancy and minimizes the storage space used.

Incremental backups:

Changes between backups are typically low. Reading and sending only the delta reduces the storage and network impact of backups.

Data integrity:

The built-in SHA-256 checksum algorithm ensures accuracy and consistency in your backups.

Remote sync:

It is possible to efficiently synchronize data to remote sites. Only deltas containing new data are transferred.

Compression:

The ultra-fast Zstandard compression is able to compress several gigabytes of data per second.

Encryption:

Backups can be encrypted on the client-side, using AES-256 GCM. This authenticated encryption (AE) mode provides very high performance on modern hardware. In addition to client-side encryption, all data is transferred via a secure TLS connection.

Tape backup:

For long-term archiving of data, Proxmox Backup Server also provides extensive support for backing up to tape and managing tape libraries.

Ransomware protection:

Protect your critical data from ransomware attacks with Proxmox Backup Server's fine-grained access control, data integrity verification, and off-site backup through remote sync and tape backup.

Web interface:

Manage the Proxmox Backup Server with the integrated, web-based user interface.

Open source:

No secrets. Proxmox Backup Server is free and open-source software. The source code is licensed under AGPL, v3.

No limits:

Proxmox Backup Server has no artificial limits for backup storage or backup-clients.

Enterprise support:

Proxmox Server Solutions GmbH offers enterprise support in the form of Proxmox Backup Server Subscription Plans. Users at every subscription level get access to the Proxmox Backup Enterprise Repository. In addition, with a Basic, Standard or Premium subscription, users have access to the Proxmox Customer Portal.

Reasons for Data Backup?

The main purpose of a backup is to protect against data loss. Data loss can be caused by both faulty hardware and human error.

A common mistake is to accidentally delete a file or folder which is still required. Virtualization can even amplify this problem, as deleting a whole virtual machine can be as easy as pressing a single button.

For administrators, backups can serve as a useful toolkit for temporarily storing data. For example, it is common practice to perform full backups before installing major software updates. If something goes wrong, you can easily restore the previous state.

Another reason for backups are legal requirements. Some data, especially business records, must be kept in a safe place for several years by law, so that they can be accessed if required.

In general, data loss is very costly as it can severely damage your business. Therefore, ensure that you perform regular backups and run restore tests.

Software Stack

Proxmox Backup Server consists of multiple components:

• A server-daemon providing, among other things, a RESTful API, super-fast asynchronous tasks, lightweight usage statistic collection, scheduling events, strict separation of privileged and unprivileged execution environments

• A JavaScript management web interface

• A management CLI tool for the server (proxmox-backup-manager)

• A client CLI tool (proxmox-backup-client) to access the server easily from any Linux amd64 environment

Aside from the web interface, most parts of Proxmox Backup Server are written in the Rust programming language.

"The Rust programming language helps you write faster, more reliable software. High-level ergonomics and low-level control are often at odds in programming language design; Rust challenges that conflict. Through balancing powerful technical capacity and a great developer experience, Rust gives you the option to control low-level details (such as memory usage) without all the hassle traditionally associated with such control."

—The Rust Programming Language

Getting Help

Enterprise Support

Users with a Proxmox Backup Server Basic, Standard or Premium Subscription Plan have access to the Proxmox Customer Portal. The customer portal provides support with guaranteed response times from the Proxmox developers. For more information or for volume discounts, please contact sales@proxmox.com.

Community Support Forum

We always encourage our users to discuss and share their knowledge using the Proxmox Community Forum. The forum is moderated by the Proxmox support team. The large user base is spread out all over the world. Needless to say that such a large forum is a great place to get information.

Mailing Lists

Proxmox Backup Server is fully open-source and contributions are welcome! Here is the primary communication channel for developers:

Mailing list for developers:

Proxmox Backup Server Development List

Bug Tracker

Proxmox runs a public bug tracker at https://bugzilla.proxmox.com. If an issue appears, file your report there. An issue can be a bug, as well as a request for a new feature or enhancement. The bug tracker helps to keep track of the issue and will send a notification once it has been solved.

License

Copyright (C) 2019-2023, Proxmox Server Solutions GmbH

This software is written by Proxmox Server Solutions GmbH <support@proxmox.com>

Proxmox Backup Server is free and open source software: you can use it, redistribute it, and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see AGPL3.

History

Backup is, and always has been, a central aspect of IT administration. The need to recover from data loss is fundamental and only increases with virtualization.

For this reason, we've been shipping a backup tool with Proxmox VE, from the beginning. This tool is called vzdump and is able to make consistent snapshots of running LXC containers and KVM virtual machines.

However, vzdump only allows for full backups. While this is fine for small backups, it becomes a burden for users with large VMs. Both backup duration and storage usage are too high for this case, especially for users who want to keep many backups of the same VMs. To solve these problems, we needed to offer deduplication and incremental backups.

Back in October 2018, development started. We investigated several technologies and frameworks and finally decided to use Rust as the implementation language, in order to provide high speed and memory efficiency. The 2018-edition of Rust seemed promising for our requirements.

In July 2020, we released the first beta version of Proxmox Backup Server, followed by the first stable version in November 2020. With support for encryption and incremental, fully deduplicated backups, Proxmox Backup offers a secure environment, which significantly reduces network load and saves valuable storage space.