Kopia

Kopia is a completely free and open-source backup tool released under the Apache License 2.0. Users can download the source code and use both the command-line interface and the graphical user interface without paying any licensing fees. It is a community-driven project developed openly on GitHub.

Kopia supports creating immutable snapshots when backing up to compatible cloud storage providers or specialized NAS devices. This prevents anyone, including an administrator with compromised credentials, from deleting or modifying the backup data until a specified retention period expires. It provides a vital safeguard against malicious file encryption.

Yes, Kopia is cross-platform and natively supports file-level backups on Windows, macOS, and Linux distributions. It also offers a KopiaUI wrapper, making it easy to manage networked backups for multiple devices from a single web dashboard. This makes it versatile for mixed-OS home servers and enterprise environments alike.

While Kopia is incredibly fast at source-side deduplication and incremental file backups, native block-level virtual machine image backups are more complex. It excels at file-level snapshots, but for bare-metal VM recovery, users often pair it with specialized virtualization tools. It is primarily an application and file-level disaster recovery solution.