ZFS-FreeBSD + postgresql performance

Hi

I would like to known if someone here have in production a FreeBSD server
with postgresql and the FS for the data of postgresql is a ZFS pool.

I'm going to buy some server with 96Go of Ram and a jbod of 12 disks (4To
each)

The purpose is to have everything on this zfs pool (except the system who
still on classic raid). So to have

many jail (~20-30) running apache/mysql/etc.
one postgresql server with all data on the zfs.

each jail use his own zfs partition. So I can use zfs send/received to have
a mirror of everything in a other server.

My question is about the performance, I known ZFS eat all memory he can
have (or almost), so what append when we run database like postgresql and
jail ? (it's also the reason of 96 Go ram).

Sorry for cross-posting but it's about 3 differents things....

Regards.

JAS

--
Albert SHIH
DIO bâtiment 15
Observatoire de Paris
5 Place Jules Janssen
92195 Meudon Cedex
France
Téléphone : +33 1 45 07 76 26/+33 6 86 69 95 71
xmpp: jas(at)obspm(dot)fr
Heure local/Local time:
mer 23 oct 2013 18:17:24 CEST