Cited on HN 5 times, 2014–2019, never outright recommendedscore 0
Years with an HN recommendation, 2007–2026
Cited as the primary source for why Netflix uses FreeBSD and UFS rather than ZFS on its CDN boxes, and for its GPL reasoning.
Scott Long of Netflix presents the architecture of the OpenConnect content delivery network at NYCBSDCon 2014. He explains why Netflix runs FreeBSD 10 on its appliances and what the future holds.
“Actually it turns out they don't really have a need for most of the features of ZFS.” (HN, 2014)
> I'm assuming whatever file system is on the disks... Netflix uses UFS+J on FreeBSD 10. Here are some notes from their talk at NYCBSDCon 2014: - 400,000 stream files per appliance. - 5,000 - 25,000 client streams per appliance. - 300 - 500 streams coming off each disk all the time. - Attempt to buffer 1MB ahead, but caching is futile. - Result is completely random disk workload. - System becomes limited by disk latency and CPU load. Video here: [this video]
Netflix talk on serving streams from FreeBSD appliances with UFS
Scott Long has summarized it a few times, eg, from [link] : • Availability of expertise, outstanding community • Works well, good vendor support • No GPL • Features used: – SUJ – gmirror – boot drive only – AIO – Dtrace, HWPMC – TCP Stack, modular CC It's missing "Integrates tightly with nginx: Async I/O and sendfile()" which Scott included in [this video] . In the video he elaborates a bit more about the GPL... edit: formatting
Scott Long on why Netflix chose FreeBSD, including the GPL
Netflix delivers all video streaming content via FreeBSD which makes up 37% of all internet traffic. [link] They also contribute to FreeBSD core. It is not just an "appliance" as some people seem to want to point to. [link] [link] [this video] In addition, a guy I met, who worked at Yahoo, told me about 25% of Yahoo still runs FreeBSD as of two years ago.
Pretty sure it's still UFS+J. They've mentioned in the past that the benefits of ZFS don't really apply to the CDN boxes: if a drive dies, it's simply removed from the local cache, and files are re-downloaded/redistributed as necessary across the remaining cache drives the next time the appliance refreshes from its upstream origin. Additionally, ZFS prefetching was actually less performant in some cases from what I remember -- or at least providing no benefit -- because of how it couldn't really anticipate the I/O patterns of video segment requests from users. Additional reference: - [link] ("…but caching is futile.") - [this video]
Netflix's reasons ZFS benefits do not apply to CDN boxes
Video list and Hacker News comment labels from HackerTube (prompted by @karpathy), released under ODC-By 1.0, built on the open-index/hacker-news archive. Hacker News data is provided by Y Combinator; comments remain the work of their authors. Video titles, channel names and thumbnails belong to their creators and are shown via YouTube. HackerTube Watch is an unofficial edition. Data export of 2026-10-31.
Plays via YouTube's privacy-enhanced embed
5 Hacker News comments
From the HN archive; up to 20 kept per video, favoring different commenters. Recommendations first.
Read more