=== OpenZFS RAIDZ Expansion update

Contact: Matthew Ahrens <matt@mahrens.org>

Links: +
link:https://github.com/openzfs/zfs/pull/12225[OpenZFS Pull Request] URL: link:https://github.com/openzfs/zfs/pull/12225[https://github.com/openzfs/zfs/pull/12225] +
link:https://youtu.be/3SUKJye54aI?t=6166[video from 2021 FreeBSD Developer Summit] URL: link:https://youtu.be/3SUKJye54aI?t=6166[https://youtu.be/3SUKJye54aI?t=6166] +
link:https://docs.google.com/presentation/d/1FeQgEwChrtNQBHfWSNsPK3Y53O5BnPh3Cz5nRa5GAQY/view[slides from 2021 FreeBSD Developer Summit] URL: link:https://docs.google.com/presentation/d/1FeQgEwChrtNQBHfWSNsPK3Y53O5BnPh3Cz5nRa5GAQY/view[https://docs.google.com/presentation/d/1FeQgEwChrtNQBHfWSNsPK3Y53O5BnPh3Cz5nRa5GAQY/view] +
link:https://arstechnica.com/gadgets/2021/06/raidz-expansion-code-lands-in-openzfs-master/[news article from Ars Technica] URL: link:https://arstechnica.com/gadgets/2021/06/raidz-expansion-code-lands-in-openzfs-master/[https://arstechnica.com/gadgets/2021/06/raidz-expansion-code-lands-in-openzfs-master/]

==== Project

This feature allows disks to be added one at a time to a RAID-Z group, expanding its capacity incrementally.
This feature is especially useful for small pools (typically with only one RAID-Z group), where there isn't sufficient hardware to add capacity by adding a whole new RAID-Z group (typically doubling the number of disks).

FreeBSD's ZFS implementation comes from the OpenZFS project.
This work will be integrated into the OpenZFS repo, with support for FreeBSD and Linux.

==== Status

The work is functionally complete, and a pull request has been opened.

==== Remaining Work

Remaining work includes some code cleanup, design documentation, addressing test failures.

We also need to solicit code reviewers and respond to code review feedback.

Sponsor: The FreeBSD Foundation