Zfs is my bug bear at the moment. You can create such wonderfully fast storage for minimal outley.
We use zfs on a range of backup bricks (3x3tb with an atom CPU and 4 gig ram giving about 5.4tb of usable space for $1200 a unit). The main problem I have is how to send data over adsl back to our central storage box (40*3tb in multiple zraid2).
The trick with this seems to be ensuring that you roll back the receivers end first. This allows you to have a clean slate to send to.
More details to come including some source code and diagrams.
