StarWind Software

We are using esxi 5.1 and eager disks.

Dual dual gig links using round robin and optimized we can saturate both links no problem, but with dedup we're getting about 33% on each link.

The iscsi server is running 12 sas disks, lsi 9266 controller 8gb and e5520 cpu

I was expecting the same saturation. What could cause it to be so slow?

High CPU usage (check it) and higher load on storage. In any case there's no point it checking current dedupe as it's for backup only (no primary VM storage).
Wait for upcoming V8 where dedupe would actually INCREASE IOPS rather then stealing them like current version does (because of the higher disk use).

oh ok. I thought that problem was fixed, based on other posts v6 was supposed to fix the dedup problem. We will just stick to the regular disk for now.

Do you suggest a raw disk or a vdisk to present over iscsi?

In my opinion vdisk is better - its more flexible.