The Dell PowerEdge R805 uses the Broadcom NetXtreme II 5708 with quad port on board NIC. This Broadcom NIC supports both a TCP/IP Offload Engine (TOE) and an iSCSI ready option. iSCSI ready means that it is possible to setup a hardware iSCSI initiator that can be used for boot from iSCSI SAN and as an offload engine for iSCSI. This iSCSI adapter shares the same physical port as the NIC that operating system uses for regular TCP/IP traffic, but has it's own MAC and IP address.

When you configure a Dell PowerEdge R805 or R905 on dell.com you will see the following option. What is referred to as iSCSI ready is the iSCSI adapter on the Broadcom 5708.



The TOE and iSCSI options are included with the R805 which means that the enabling licensing key has already been loaded. The licensing key is required to enable the iSCSI Adapter function, so when using a system that does not come with the function enabled - the licensing key will need to be added.

To configure the iSCSI adapter download the latest version of the drivers for the NetXtreme II 5708 and Broadcom Advanced Control Suite (BACS) from broadcom - http://www.broadcom.com/support/ethernet_nic/netxtremeii.phpInstall

Install first the updated driver and then the BACS management application.

The iSCSI ready hardware based adapters will not appear in windows network management. So in order to set the IP address for them you have to use the BACS management tool.

Start BACS and expand the iSCSI controllers section, then select the adapter that you want to enable for iSCSI. Click on the configurations tab to set the IP address for the iSCSI adapter. The picture below shows the iSCSI IP being set for the third NIC.




Once you have the iSCSI IP set you will now be able to use the standard iSCSI Initiator management tool in windows to manage the connection. The difference is that you will now have the choice of the broadcom iSCSI ready adapters and the Microsoft software initiator as seen in the following screen-shot.



After selecting the Broadcom iSCSI adapter that was configured using BACS, the IP address that you set will be the only available source IP as seen in the next screen-shot.



In order to test if the hardware based iSCSI adapter vs the Microsoft software based iSCSI adapter a quick test was done. The same four iSCSI LUNs were attached to the test R805 with both the hardware and software based iSCSI initiators. The R805 was installed with Windows Server 2008 x64 Enterprise Edition with the Hyper-V role enabled. The test workload was a set of 12 Hyper-V VMs spread evenly across the four LUNs. Each VM was running SQL Server 2005 on Windows Server 2008. The Dell DVD Store database was loaded and stressed from a separate PowerEdge 2970 server, placing a fairly high stress on the test R805 server. The graph below shows the results from the same test run first with the software based iSCSI initiator and then with the hardware based iSCSI initiator.



For this specific workload a reduction in overall CPU utilization (blue line) was seen. The red line shows the %Total Run Time for the Hypervisor logical processors which represents the system utilization consumed by the activity in the VMs. Because the iSCSI initiator is run on the parent partition, that is where the difference in CPU utilization is mostly observed. Different workloads will have different results and a reduction in CPU utilization is not guaranteed for the hardware based iSCSI adapter.