It's not so bad if you build the system taking these things into account 
(much easier if you wait long enough to read about others' experiences 
:-). We built our BSD ZFS systems using inexpensive Intel 313 SSDs for 
the log devices. I can't say that they're the best possible choice, 
opinions vary all over the map, but the box is currently happily 
accepting 2Gbps continuous NFS writes, which seems pretty decent.

Graham

On 7/24/2013 5:36 PM, Paul Robert Marino wrote:
> ZFS is a performance nightmare if you plan to export it via NFS because
> of a core design conflict with how NFS locking and the ZIL journal in
> ZFS. Its not just a linux issue it effects Solaris and BSD as well. My
> only experience with ZFS was on a Solaris NFS server and we had to get a
> dedicated flash backed ram drive for the ZIL to fix our performance
> issues, and let me tell you sun charged us a small fortune for the card.
> Aside from that most of the cool features are available in XFS if you
> dive deep enough into the documentation though most of them like multi
> disk spanning can be handled now by LVM or MD but are at least in my
> opinion handled better by hardware raid. Though I will admit the being
> able to move your journal to a separate faster volume to increase
> performance is very cool and that's only a feature I've seen in XFS and ZFS.