ZFS was designed at Sun by Jeff Bonwick and Bill Moore beginning in 2001 and released in 2005 as a filesystem that simply refused to lose your data. Copy-on-write, end-to-end checksums, self-healing RAID, snapshots, clones, compression, deduplication — everything a storage administrator could want in a single coherent stack. It was, and largely remains, technically magnificent. The catch: ZFS is hungry. Its deduplication table lives in RAM; run dedup on modest hardware and your system bogs to a crawl as the dedup table spills to disk. The licensing situation prevented it shipping in the Linux kernel for over a decade, relegating it to FreeBSD and a FUSE module on Linux that nobody trusted for production. ZFS on Linux arrived properly as OpenZFS in 2013. Admins who use it tend toward quiet evangelical certainty that everyone else is wrong. They are, on the technical merits, largely correct.
