Only great things to say about FoundationDB. We've been using it for about a year now. Got a tiny, live cluster of 35+ commodity machines (started with 3 a year ago), about 5TB capacity and growing. Been removing and adding servers (on live cluster) without a glitch. We've got another 100TB cluster in testing now. Of all the things, we're actually using it as a distributed file system.<p>We've tried Ceph, GlusterFS, HDFS, MinIO and some others, and eventually decided on a custom FDB solution. It's a breeze to setup, and seems to eclipse others in performance [0] and reliability - Kyle (aphyr) the author of Jepsen series on distributed systems correctness, said: "haven't tested foundation in part because their testing appears to be waaaay more rigorous than mine." [1]<p>The way we use FDB, if anyone is interested, is we simply split files into small chunks (per FDB data design recommendations), and store all file's & folder's meta data in FDB such as byte count, create/access/write times, permissions, and a lot more. Folders are handled by the builtin Directory layer [2].<p>[0] <a href="https://apple.github.io/foundationdb/performance.html" rel="nofollow">https://apple.github.io/foundationdb/performance.html</a><p>[1] <a href="https://web.archive.org/web/20150312112552/http://blog.foundationdb.com/call-me-maybe-foundationdb-vs-jepsen" rel="nofollow">https://web.archive.org/web/20150312112552/http://blog.found...</a><p>[2] <a href="https://forums.foundationdb.org/t/whats-the-purpose-of-the-directory-layer/677" rel="nofollow">https://forums.foundationdb.org/t/whats-the-purpose-of-the-d...</a>