ZFS storage and backup

[infoomatic]

Hi listmembers,

I am about to migrate our mailservices to FreeBSD + ZFS. Thus, before
entering the sheer endless  stage of performance testing, I thought I
would ask here kindly for all kinds of information.

My setups are nothing special with few users, however, I would like to
have a nice setup, maybe some of you could contribute to this thread. We
are using slow spinning disks, but we may consider using ssds in a
not-so-distant future.

*) storages: any infos on ZFS options or whether to use mdbox or sdbox,
and what configs/options regarding compression etc.

*) backup: what is a best practice regarding backups? - using only the
dovecot tools or leveraging the great features of ZFS (or both) with
snapshots etc.?

Thanks for all sorts of infos, probably saving me quite some time
evaluating different options!

Robert