We've setup an md3220i SAN to be used against vmware 5.1. When inside a VM on this SAN we tried copying a file multiple times creating multiple/sessions streams. When doing this, it's only the latest stream that runs and all others are paused untill the active one is finished.
Is this something you can change in vmware? or could it be a controller issue/setting? We have 4 luns with 8 paths to each one. If you need any additional information - just ask! :)
This was solved by making the SAN connections 1 to 1 via the switchports. Allowing all the SAN vlans on all the ports messed the setup up.