Q: Infortrend Settings For Xsan?

We are installing our first Infortrend-based Xsan, using (3) S16F-RG1840 chassis. We've started with settings that have worked well in our Promise installs, but wanted to see if anyone had advice for using Infortrend arrays in an Xsan 2 environment for HD Video with FCP, Cinema 4D, and Maya 2011 clients, in particular:

1) RAID LUN Stripe: 64 or 128K?

2) A/V Optimization: On or Off? This seems to turn on read pre-fetching, but they mention that is disables controller fail-over, which we really need. In other arrays (like a Promise), pre-fetching doesn't disable fail-over. Is there a way to have both?

3) With Promise arrays we have often used 64K blocks with a 16 block stripe breadth. Would Infortrend arrays work better with a different combination?

The three chassis were purchased before we were involved, and because there are only three, they don't allow us to create the 4-LUN pools that would be optimal for HD Video. However they are all RAID controllers, so that gives us some flexibility, and the advantage of giving each LUN it's own fibre connection to the switch. At the moment we are doing the following:

RAID1
-MDJ01 -> Controller A (Top), Port 0
-DATA01 -> Controller A (Top), Port 1
-DATA02 -> Controller B (Bottom), Port 0

RAID2
-DATA03 -> Controller A (Top), Port 0
-DATA04 -> Controller B (Bottom), Port 0

RAID3
-DATA05 -> Controller A (Top), Port 0
-DATA06 -> Controller B (Bottom), Port 0

Our initial idea has been to create three, 2-LUN storage pools, which would at least allow for easy expansion later, one (2-LUN) chassis at a time. So far we are getting good results, but wanted to see if anyone had any other ideas that have proven to work well.

Finally, Infortrend arrays cost quite a bit less than Promise or Active, and I'd be interested in hearing whether any of you feel there is a noticeable difference in performance or reliability.

Thanks,

JM