I have an HP guy telling me that he has been told that vSphere does not support round robin using iSCSI
I think he said that you can select round robin as the PSP, but that if you have multiple vmkernels loaded and each assigned to it's own nic, that it will not actually make use of multiple paths to any given LUN
I thought that was one of the major feature improvements of 4.1 iSCSI
Am I confused?
vSphere 4.x has no issues with Round Robin on iSCSI.
It is up to the hardware vendor to confirm whether Round Robin is supported on their array which is why you rarely see it in the HCL.
Most Active-Active arrays will support Round Robin, and most ALUA based Active-Passive arrays will also support it.
Just to be sure I'd check with HP to confirm this.
The 1:1 mapping (1 x vmkernel port assigned with 1 x NIC) is VMware best practice for all software iSCSI configurations regardless on whether Round Robin is being used.