One of the more popular posts I’ve done over the last few months has been how to configure a standard vSwitch to allow multiple paths to the storage using the software iSCSI initiator in vSphere 4.0
The only problem here was this could only be done with a standard vSwitch and trying to configure on a virtual distributed switch resulted in the error “Add nic failed in IMA” (VMware also confirmed this was a bug)
When vSphere 4 update 1 was released I went straight to the release notes to see if this problem had been resolved, but found no mention of it. After a quick install I found the error no longer occurred, but unfortunately did not have my Celerra simulator setup to test conclusively.
Good news, last night I set this up using the exact configuration used previously and found this problem has been resolved in update 1.
Here are some screenshots showing everything working as expected using the dVswitch.
Virtual Distributed Switch
In this screenshot you can see I have multiple port groups configured, each with its own VMKernel port.
Here the device view shows the 2GB lun presented from the Celerra. You can also see 2 paths are now being reported.
This screenshot was taken after I changed the path selection policy to “Round Robin” which is no longer considered experimental (as it was with ESX 3.x) I now have 2 avtive paths.
I got a few emails over the last month asking if I had tested this yet so I hope this helps and if your looking for the new vSphere iSCSI configuration guide, you can find this here.
Also here is a great white paper on migration and configuration of virtual distributed switches.