Developer resources

Ways to contact people

• ZFS experts
• Mailing list
• IRC: #openzfs on freenode (web interface)
• Twitter: @openzfs
• OpenZFS Office Hours: rotating the leader/owner
• Pointers to other mailing lists and repos?

Ongoing work

• Test framework
• One of our goals is to reduce code differences.
  • list of platform code differences
• Projects
  • ZFS Channel Programs

Implementation documentation

• Links to source code are on the Distributions page
• Architectural/high-level documentation about general OpenZFS concepts
  • zfs send
  • administrative commands (e.g. zfs snapshot -r pool/fs@snap)
  • zfs I/O
• The FreeBSD book has a great chapter on ZFS - this is probably the best overview available for new developers.

Materials on other websites

ZFS On-Disk Specification – Draft (ZFSOnDiskFormat.pdf, Sun Microsystems, Inc., 2006-08)

• sometimes known as the ZFS On-Disk Format document
• outdated, but "hasn't changed that much, and backwards compatibility dictates that it's still useful as a base of knowledge"; "It's the closest thing we have to a comprehensive overview – and it's still mostly applicable, it just doesn't cover newer stuff … like SAs".

Examining ZFS On-Disk Format Using mdb and zdb (2008-06-28)

• a forty-three minute video of Max Bruning presenting to the OpenSolaris Developer Conference in Prague.

The source tour (archive) describes the various subcomponents in ZFS.

Blog posts on ZFS features

Adaptive Replacement Cache, also known as Adjustable Replacement Cache (ARC)

• Some insight into the read cache of ZFS - or: The ARC - c0t0d0s0.org (2009-02-20)
• Brendan's blog » Activity of the ZFS ARC (2012-01-09)
• Aaron Toponce : ZFS Administration, Part IV- The Adjustable Replacement Cache (2012-12-07)

Block allocation

• ZFS Block Allocation (Jeff Bonwick's Blog) (2006-11-04)

Deduplication

• ZFS Deduplication (Jeff Bonwick's Blog) (2009-11-01)

Encryption

• ZFS encryption what is on disk ? (darren_moffat@blog$ cat /dev/mem | grep /dev/urandom) (2010-11-19)

Hot spares

• ZFS Hot Spares (Eric Schrock's Weblog) (2006-06-06)

Level 2 Adaptive Replacement Cache, also known as Level 2 Adjustable Replacement Cache (L2ARC)

• ZFS L2ARC (Brendan Gregg) (2008-07-22)
• L2ARC Screenshots (Brendan Gregg) (2009-01-30)
• arcstat.pl updated for L2ARC statistics | Mike Harsch's Blog (2010-09-08)
• Days of a mirror admin: How the L2ARC works (2011-12)
• Aaron Toponce : ZFS Administration, Part IV- The Adjustable Replacement Cache (2012-12-07)

RAID-Z

• RAID-Z (Jeff Bonwick's Blog) (2005-11-17)
• ZFS RAIDZ stripe width, or: How I Learned to Stop Worrying and Love RAIDZ (Matt Ahrens' Blog, 2014-6-15)

Scrub and resilver

• New Scrub Code (Matthew Ahrens' Weblog) (2008-12-15)

Snapshots

• Is it magic? (Matthew Ahrens' Weblog) (2005-11-17)

Space maps

• Space Maps (Jeff Bonwick's Blog) (2007-09-13)
• OpenZFS code walk of metaslabs (Delphix's open source blog) (2015-01-26)

Transaction groups

• Transaction Groups (Adam Leventhal's blog) (2012-12-13)

VFS interactions

• FreeBSD VFS layer (Andry Gapon's blog) (2014-01-14)

Write Throttle

• Write Throttle 1.0 (Adam Leventhal's blog) (2013-12-27)
• Write Throttle in OpenZFS (Adam Leventhal's blog) (2014-2-10)
• Tuning the OpenZFS Write Throttle (Adam Leventhal's blog) (2014-8-31)

ZFS Intent Log (ZIL)

• ZFS: The Lumberjack (Neil Perrin's Weblog) (2005-11-16)
• Aaron Toponce : ZFS Administration, Part III- The ZFS Intent Log (2012-12-06)

Repo-specific developer documentation

• Illumos integration process
• Information about how to develop ZFS for the different distributions/pointers to them (e.g., how to build illumos)
  • in particular, documentation about how to test and possibly scripts for building
  • needs to be written/links provided by reps from those communities.