Julien Cassette developed ZFS reflink support for both the Radarr and Sonarr repositories, extending copy-on-write file transfer capabilities to ZFS volumes. By updating backend C# services to invoke TryCreateRefLink and TryRenameFile during copy and move operations, Julien ensured parity between ZFS and existing Btrfs workflows. This system programming work improved large-file transfer performance and storage efficiency, reducing I/O load for media libraries. Julien’s approach integrated cross-filesystem logic into the backend, laying groundwork for future optimizations. The work demonstrated depth in file system operations and backend development, delivering robust, maintainable enhancements without introducing bugs during the implementation period.