Here is the setup.
(2) HP 2910al switches, ports 1-12 set for Jumbo Frames and Flow Control. Ports 1-6 Tagged for VLAN 1 with an IP Subnet of 192.168.100.x
(2) Dell R710's with (2) NICs. I've set port bindings, configured VLAN tagging for storage network. These two physical NIC ports are plugged into ports 5 and 6 respectively on both switches.
(1) Nimble array setup on storage network, set to untagged on HP switches.
I have (2) IBM servers in production that are successfully connected to the Nimble array. For whatever reason the Dell servers using Dynamic Discovery won't connect to the iscsi target. I can statically assign the Nimble array, it will see the array, however when adding luns it hangs. I can ping both the nimble array and the ESX hosts from each device respectively. I've confirmed about a dozen times that the switches are configured the same for the Dell Servers as well as the IBM Servers. I've upgraded from esx 5.0 to 5.1, rebooted the host 6-7 times, removed and added the iSCSI Software Adapter and worked with Nimble support for about 6 hours with no resolution. Any help would be greatly appreciated!