However, I found the software iSCSI is more than enough and it’s actually more flexible in terms of Maximum Number of Offload Connections (see my December 1, 2010 comment) and CPU wise, it only takes 1-2% more CPU with Xeon 5600 series, but may take more (close to 20-30%) if you have 5400 series.

Performance wise, I did test both, not much difference really, of course, you can use Boot from SAN if you have that iSCSI Key, but most people recommend to use a local storage or SD card instead for installing ESX/ESXi.

Update:

Sorry, I misread your question. You need to contact Dell regrding this issue, the stand alone Quad-Port Broadcom NIC with ISOE should appear in ESX as HBA EVEN WITHOUT the on-board iSOE key.

Do you need the iSCSI Offload Key for the PE2950?

If the Broadcom NetXtreme II 5709 have it embedded, how come the PE2950 Bios and ESXi 4.1 do not recognized this device?

Thanks for the re’

There are physical limitations for the Broadcom iSOE cards (iS You will run out of resources on the cards which will limit the number of iSCSI connections when configured as HBA’s as follows:

Table 2: Maximum Number of Offload Connections

Offload First Come First Served Reserved Resources Maximum Number of Connections
TOE only Selected – 1024
TOE only – Selected 864
iSCSI only Selected – Between 7 and 100
iSCSI only – Selected 28

It has been my experience that HBA mode with First Come First Served reservation policy can support 64
connections reliably however, there may be other factors in the server that may influence that number yielding less connections.

To answer your question on how much additional performance you are likely to gain – remember, this type of configuration benefits the SERVER. If you have a high quality honking server class server, it is my opinion that you will see less than a 10% performance benefit which would be in the form of server CPU utilization; nothing else.