FreeBSD ZFS snapshots and "previous versions"

Matthew Seaman matthew at
Tue Mar 29 16:08:31 UTC 2016

On 2016/03/29 16:35, Dennis Steinkamp wrote:
> - Are OmniOS and FreeBSD are on the same ZFS version (or at least equal
> feature wise)

Pretty much, yes.  Since the end of the Oracle code, there's hasn't been
a version number per-se, but a set of feature flags.  Given you're using
a system based on OpenZFS code, so long as you have support for the same
set of feature flags then you should have compatible functionality.

You can see what feature-flags are supported on any system by running
'zpool upgrade -v' -- this is what you get on a recent 10.3-PRERELEASE

% zpool upgrade -v
This system supports ZFS pool feature flags.

The following features are supported:

async_destroy                         (read-only compatible)
     Destroy filesystems asynchronously.
empty_bpobj                           (read-only compatible)
     Snapshots use less space.
     LZ4 compression algorithm support.
     Crash dumps to multiple vdev pools.
spacemap_histogram                    (read-only compatible)
     Spacemaps maintain space histograms.
enabled_txg                           (read-only compatible)
     Record txg at which a feature is enabled
     Retain hole birth txg for more precise zfs send
     Enhanced dataset functionality, used by other features.
     Blocks which compress very well use even less space.
bookmarks                             (read-only compatible)
     "zfs bookmark" command
filesystem_limits                     (read-only compatible)
     Filesystem and snapshot limits.
     Support for blocks larger than 128KB.

The following legacy versions are also supported:

---  --------------------------------------------------------
 1   Initial ZFS version
 2   Ditto blocks (replicated metadata)
 3   Hot spares and double parity RAID-Z
 4   zpool history
 5   Compression using the gzip algorithm
 6   bootfs pool property
 7   Separate intent log devices
 8   Delegated administration
 9   refquota and refreservation properties
 10  Cache devices
 11  Improved scrub performance
 12  Snapshot properties
 13  snapused property
 14  passthrough-x aclinherit
 15  user/group space accounting
 16  stmf property support
 17  Triple-parity RAID-Z
 18  Snapshot user holds
 19  Log device removal
 20  Compression using zle (zero-length encoding)
 21  Deduplication
 22  Received properties
 23  Slim ZIL
 24  System attributes
 25  Improved scrub stats
 26  Improved snapshot deletion performance
 27  Improved snapshot creation performance
 28  Multiple vdev replacements

For more information on a particular version, including supported releases,
see the ZFS Administration Guide.


> - Am i able to build a prooduction stable zfs filer with freebsd that
> supports zfs snapshots for windows clients the same way OmniOS does.


In fact, for NAS use, take a look at which is a
project built on FreeBSD and ZFS.



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