ZFS: The Last Word in File Systems Part 1
Why Hacker News recommends it
HN recommends it as the definitive explanation of ZFS design straight from its inventors, with war stories about data integrity.
What it is
Jeff Bonwick and Bill Moore, the creators of ZFS, present 'ZFS: The Last Word in File Systems' at the 2008 SNIA Software Developers' Conference. They explain the design, including copy-on-write, checksumming and avoiding the write hole.
Recommended by 4 HN commenters across 4 different months, 2016 to 2026.
What Hacker News said
Strong rec tnorgaard · 2016-06 · on “A ZFS developer’s analysis of Apple’s new APFS file system”
I would recommend anybody interested in filesystems to watch Jeff Bonwick (ZFS inventor) explain the design of ZFS: [this video] . They have a few very nice war stories explaining why they found it useful to have the user data checksummed as well.
Strong rec throw0101a · 2019-10 · on “Ubuntu installer now supports ZFS on the boot partition”
> Is ZFS any good? The presentation "ZFS: The Last Word in File Systems" from its debut in 2008 is a good introduction. Part 1 (of 3) probably best explains how different it is from just about anything else out there (even now, in 2019): * [this video] Part 2 show some extra niceties / features, and Part 3 is a demo and Q&A. Watching Part 1 at least is worth it for anyone curious; 2 and 3 are optional.
Strong rec jorangreef · 2023-11 · on “”
ZFS was an inspiration for TigerBeetle. I love this talk by Jeff Bonwick and Bill Moore: “ZFS: The Last Word in File Systems” [this video]
Recommends solarengineer · 2026-01 · on “FreeBSD: Home NAS, part 1 – configuring ZFS mirror (RAID1)”
ZFS: The last word in File Systems: Part 1: [this video] Part 2: [LINK] ZFS In the trenches: [LINK] Some good stuff here: [LINK]
Cites throw0101a · 2020-09 · on “Preserving data integrity: A ZFS-inspired storage system”
Well, ZFS isn't exactly monolithic if you look under the hood: it has the ZPL (files, directories), DMU (objects, transactions on those objects), SPA (actual disk I/O). A potato-quality video from 2008 with Moore and Bonwick, the creators (timestamped to relevant section): * [this video]
Cites throw0101a · 2021-04 · on “Btrfs on Zoned Block Devices”
> initial issues You mean like the current advice not to use anything except mirroring and striping (RAID-0/1/10)? > Parity may be inconsistent after a crash (the "write hole"). The problem born when after "an unclean shutdown" a disk failure happens. But these are two distinct failures. These together break the BTRFS raid5 redundancy. If you run a scrub process after "an unclean shutdown" (with no disk failure in between) those data which match their checksum can still be read out while the mismatched data are lost forever. * [LINK] I've been using ZFS since it came out on Solaris 10 over a decade ago and it was specifically designed not to have a write hole due to its COW/ACID nature. See