EBS snapshot backups from a FreeBSD zfs file system: zpool freeze?

[Freddie Cash]

On Mon, Jul 8, 2013 at 3:31 PM, Berend de Boer <berend at pobox.com> wrote:

> >>>>> "Freddie" == Freddie Cash <fjwcash at gmail.com> writes:
>
>     Freddie> At which point, it would make more sense taking the
>     Freddie> discussion upstream to Illumos to find a way to quiesce a
>     Freddie> ZFS pool in such a way that EBS backups would work.  Once
>     Freddie> that is done, then it can filter downstream to FreeBSD,
>     Freddie> Linux, and others.
>
> Great tip. Didn't know exactly if the ZFS implementation in FreeBSD
> was forked or not. I see on their home page about submitting patches
> :-)
>

The FreeBSD implementation of ZFS isn't 100% identical to the Illumos (aka
"reference") implementation, mainly due to GEOM; however, the FreeBSD ZFS
maintainers try to keep it at feature parity with Illumos (and even push
patches upstream that get added to Illumos).

Same with the Linux implementation of ZFS, although there are more changes
made to that one to shoehorn it into that wonderful mess they call "a
storage stack".  :)  There are a handful of features available in the
ZFS-on-Linux implementation that aren't anywhere else (like "-o ashift="
for zpool create/add).

All in all, the ZFS-using OS projects try to stay as close to the Illumos
version as is reasonable for the OS.

It certainly would be interesting to have a "zfs freeze" and/or a "zpool
freeze" (depending on where you want to quiesce things), but it may not
play into how ZFS works (wanting to have complete control over the block
devices, meaning no special magic underneath like block-level snapshots).
:)  Or, it may be the "next great feature" of ZFS.  :)

-- 
Freddie Cash
fjwcash at gmail.com