Features

Proxmox Backup is a stand-alone solution. The open-source nature of the Proxmox software stack means that you get a secure, flexible product that you can trust. The source code is free and open-source, licensed under the GNU Affero General Public License, v3 (GNU AGPLv3). Thus, you are free to use the software, inspect the source code at any time, or contribute to the project yourself.

The whole Proxmox Backup software stack is written in Rust, a modern, fast, and memory-efficient language. Rust provides high speed and memory efficiency, due in part to its lack of runtime and garbage collector. Its rich type system and ownership model guarantee memory-safety and thread-safety.

Backups are sent incrementally from the client to the Proxmox Backup Server, where data is then deduplicated. Typically, changes between periodic backups are low. Reading and sending only the changes reduces the storage space used and the network impact.

Periodic backups usually produce large amounts of duplicate data. The deduplication layer in the Proxmox Backup solution reduces the amount of duplicate data, reducing the physical space required for data storage.

When doing deduplication, there are different strategies to get optimal results in terms of performance and/or deduplication rates. Depending on the type of data, data can be split into fixed or variable sized chunks; Proxmox Backup Server supports both strategies.

Proxmox uses the ultra-fast Zstandard (ZSTD) compression which is able to compress several gigabytes of data per second. ZSTD is characterized by its high compression ratio and very fast compression speed.

With Proxmox Backup Server, all client-to-server traffic can be encrypted to safeguard data integrity. For high performance, the authenticated encryption is done on the client-side with AES-256 in Galois/Counter Mode (GCM). As your data is encrypted before it reaches the server, the data is useless to unauthorized users accessing the server.

You can further increase security by generating a master key to store and recover encryption keys. This master key is created as an RSA public/private key pair, and then used to securely store the backup encryption key itself alongside the backup. Furthermore, you can print the secret encryption key, so that it's safe from any system disaster.

Proxmox Backup protects your data against unauthorized access. Moreover, the available range of access control options help to ensure that users are limited to only the level of access they require.

There are also several authentication realms available: Linux PAM for system users, OpenID Connect for authentication through OpenID, and a Proxmox Backup authentication server for handling permissions and data ownership. There is also wide array of user roles (group permission sets), which specify exactly what each user is allowed to do on the server.

Proxmox Backup Server uses a built-in SHA-256 checksum algorithm, to ensure the accuracy and consistency of your data. Within each backup, a manifest file (index.json) is created, which contains a list of all the backup files, along with their sizes and checksums. This manifest file is used to verify the integrity of each backup. You can schedule regular backup verification to detect bit rot and confirm that backups are safe.

Checksumming is also used in the deduplication layer to detect identical blocks of data. This is ideal for efficiently storing multiple VMs with identical operating systems, as if they all share a similar data structure, only one copy of that will need to be stored.

In addition to being used for backup verification, the checksum algorithm is also used in deduplication to detect common data between backups of different machines. This can greatly reduce the storage needed to store, for example, multiple VMs that use an identical operating system.

A ransomware attack and encryption of your files and folders is a disaster for any business. Reliable backups and fast recovery can help limit the damage. Proxmox Backup Server includes several features to efficiently respond to a ransomware incident; with fine-grained access control, data integrity verification, and the possibility to create off-site backups through remote sync and tape backups, the Proxmox solution helps you plan your ransomware defense strategy and ensures that your critical data stays protected.

Proxmox Backup Server comes with an integrated, graphical user interface (GUI) to manage the server. This means that you can carry out all administration tasks through your web browser (via https://youripaddress:8007). The web interface also provides a built-in console, so if you prefer the command line or need some extra control, you have a lot of options.

The user interface comes with an array of options for administrating the server:

• Get a quick overview of the most crucial information from the dashboard.
• Easily create and mange datastores.
• Browse file backups and select for restore.
• Monitor tasks, logs and resource usage.
• Manage users, access permissions, remote stores, and subscriptions.
• Access a secure HTML5 console.
• Manage network configuration and interfaces.

For advanced users who are used to the comfort of the Unix shell, Proxmox provides a command line interface to accomplish special or very advanced tasks. The command line interface has intelligent tab completion and full UNIX man page documentation.

REST API

Proxmox Backup Server uses a RESTful API. We use JSON as the primary data format, and the whole API is formally defined using JSON Schema. This enables fast and easy integration for 3rd party management tools.

• Support for linear Tape-Open generation 5 (LTO-5) and later (with best-effort support for LTO-4), including hardware encryption.
• Flexible retention policies: always recycle tapes, never recycle tapes, recycle tapes after a particular calendar event, etc.
• Support for various tape autoloaders with the ‘pmtx’ tool (mtx tool rewritten in Rust).
• Configuration via the web interface.

In daily use, it helps to label tape cartridges so you can easily identify them. If you use a tape library, you have to add bar code labels in order to identify them.

You can use a small web-app to print these labels: Proxmox LTO Barcode Generator