Currently running PTS on the HW RAID with ZFS on top using a 64GB L2ARC, so should get results in about eight hours or so. In the meantime, to respond to some of the input:

Quote Originally Posted by Andi64 View Post
But, if you seek performance, you should use at least 8GB RAM, and I would recommend 16GB or more if possible.
Current build is using 16GB, which is basically the maximum capacity I can give it given that mITX boards only have two DIMM slots - well, that, and 16GB density modules are practically non-existent.
SSD for ZIL and L2ARC is useless unless you know what you are doing. First of all, for a ZIL log you'd need 2 SSD in RAID1, and only the sync writes will see a boost in performance. CIFS, AFP or iSCSI (Windows client) won't see any performance benefit 'cause they don't write in sync.
I understand that the performance benefits will only be seen in specific write scenarios, but given that I have a massive amount of unused SSD space, even allowing for some heavy over-provisioning, and ZIL will only benefit from ~2-3GB space, I don't really see a reason not to As for the RAID concern, I am given to understand that this was only a necessity in earlier versions of ZFS where ZIL failure would hose a pool. This issue has been corrected in more recent builds.
Instead of throwing SSDs for more performance, which won't happen because of the way it works (again, unless you have a lot of sync writes and/or you work with more data that could fit in your RAM) I would buy 32GB ECC RAM
Sadly, as above, there is no ECC option in the mITX form factor, otherwise I definitely would!
Quote Originally Posted by tiro_uspsss View Post
highly likely cause running a RAID array with ZFS on top is virtually a no-no / highly unrecommended!
From my understanding, it's really more a case of that the full featureset of ZFS doesn't really come into play when not running raw drives, or preferably using RAID-Z parity implementations. But even with ZFS running on top of a logical drive, features like snapshots, export/importability, etc are still useful - the question is whether the performance cost/benefit equation works out favourably
Quote Originally Posted by Baenwort View Post
Just wanted to give an encouraging word that I at least am following this to see where you end up.

I'm about to start my own journey down this path and I'm debating the merits of sticking with a HW RAID card over ZFS software RAID. I'm also enticed by ZFS but leery of discarding a already in hand HW card. You're build is very similar to the one I'm contemplating with the exception of ECC ram and my plan to use an old Intel X25 I have.
Heh, thanks - there's a real dearth of actual numbers-based analysis, isn't there! As always, it seems the best solution is just to muck in and do it yourself :P