I aggree with the fact that replication must not impact read performance.

My ESXi 4 is in MPIO support RR Vmware : i see activity on my two ETH for iISCSI traffic (but may it's not working...)

So what is your teaming mode in DSS to get 170Mb / s in read ?

I tried Balance-RR (lower read performance) and Balance ALB.

What is yours ?