You may have heard about NIC teaming – when you use two or more Network Interface for load balancing, failover, and speed (throughput). The important thing is to know that Microsoft does not support this. By not support this I mean that the driver for NIC teaming is provided by the vendor. I should also mention that most of the time the NIC teaming works, but it often proves that it is the root reason for some errors or other mystic behavior in your virtual environment. (Failover Cluster, ISCSI, etc.) The NIC teaming is done at the physical level and not at the virtual level. So keep that in mind when you create virtual networks and dedicate one of your NICs installed on the host.
Another option that provides much the same as NIC teaming is MPIO. This is supported and I find it very robust and useful. I have never had a problem after a ISCSI/MPIO configuration – compared to NIC teaming which often brings a whole lot of work to find the accurate drivers, requiring the firmware to be updated and so on.
If you ever have asked a question at the forums, mentioned that you have a problem and the words ‘NIC Teaming’ shows up, most of the guys would definitely recommend disabling NIC teaming first thing first to eliminate that as the root reason.
How to configure ISCSI with MPIO:
1. Open the ISCSI initioator
2. Add the ISCSI portal
3. Connect to the available targets in the Targets tab
4. Check enable multipath and add the specific target-initiator pair in one of the ISCSI networks
5. Install the MPIO feature in Server Manager
6. Go to Administration tools and click MPIO
7. In the Discover multi-path tab, click add support for ISCSI devices
8. You will be ask to restart Windows – Do it J
9. After start up, launch ISCSI-initiator, select targets and properties
10. Click Add Session and add the target-initiator pair in the remaining ISCSI network
11. Click devices, and you`ll see only one device if MPIO is configured properly
12. Click MPIO and see load balancing policies and the connections to the ISCSI device