Help testing ZFS v28 in FreeBSD

Pawel Jakub Dawidek has released a patch [1] to test ZFS version 28 in FreeBSD development version (9-CURRENT).
The patch is highly experimental and not guaranteed to work correctly. We want to correct any bugs and issues related to this patch.

What is new in v28 (compared to v15)?

  • data deduplication
  • triple parity RAIDZ
  • removal of log devices
  • zfs diff
  • zpool split
  • snapshot holds

You can read more about various ZFS pool versions in my previous article [2].
To patch and compile, you may need the following patches: (from Pawel Jakub Dawidek) (from Pawel Jakub Dawidek) (optional, v19 boot support)

To correctly apply the patches, bunzip2 the first patch and use the following commands in the following order:
cd /usr/src
patch -E -p0 < /path/to/zfs_20100831.patch
patch -E -p0 < /path/to/atomic.h.patch
patch -E -p0 < /path/to/head-zfs-v19-boot.patch (optional, v19 boot support)

Users who do not want to patch and compile can try the following:

  • Virtualbox appliance from Pawel Jakub Dawidek
  • mfsBSD ISO image of 9-CURRENT-amd64 with zfsinstall and ZFS v28 (v19 boot support)

For more information on mfsBSD and the usage of zfsinstall (ZFS-on-root) see its homepage [3].

Please help us testing and submit any bug reports found to the freebsd-current ( or freebsd-fs ( mailing lists.
To make our bug busting easier, please create a debugging environment as specified in [1].
Please ignore all the LOR (Lock Order Reversal) reports from WITNESS (there will be many) and don’t report these.

Thank you very much for participating!

[1] ZFS v28 patch announcement from Pawel Jakub Dawidek
[2] ZFS pool and filesystem versions (
[3] mfsBSD Homepage

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