ZFs

ZFS is a combined file system and logical volume manager originally developed by Sun Microsystems and first released for the Solaris operating system in 2005. It is designed to provide large storage capacity, strong data integrity, and streamlined administration by integrating disk pooling, volume management, and the file system into a single solution.

ZFS organizes storage as zpools, which are composed of virtual devices (vdevs) that can be made from mirrors or RAID-Z configurations. This pooled model allows disks to be added or expanded online. ZFS uses a copy-on-write transactional model, so writes create new data blocks and metadata while old copies remain until successfully committed. Every block is checksummed, enabling end-to-end data integrity and automatic repair if redundancy is available. Regular scrub operations verify data integrity and help detect silent data corruption.

Key features include snapshots and clones for point-in-time backups and testing, as well as send/receive for efficient replication. Optional features cover data compression, deduplication, and native encryption in modern OpenZFS implementations. ZFS also provides datasets and filesystems with fine-grained quotas, reservations, and per-dataset properties, along with built-in resistance to fragmentation and rapid resilience to disk failures. Caching via the adaptive replacement cache (ARC) and, on some platforms, secondary caching via L2ARC, can improve performance.

Licensing and platforms: the original ZFS source was released under the Common Development and Distribution License (CDDL). OpenZFS is a community-driven project maintaining ZFS across platforms, including ZFS on Linux, FreeBSD, and Illumos-based systems. Linux users typically access ZFS through ZFS on Linux, a port with its own integration considerations and licensing caveats.