I was told that using an iSCSI driver with existing network adapter would downgrade performance dramatically than using an iSCSI adapter. But has anyone really tested it out yet? What kind of performance downgrade are we talking about here?
Are you aware of any NIC vendors already incorporating what you called a TOE into their NIC?
An agent-based solution does not implement the iSCSI or TCP/IP protocol in firmware. This means the servers CPU has more processing overhead than with a true iSCSI adapter. (Each I/O request must be translated through the agent for output over the network interface.) I have not personally tested this but have been told by some of the iSCSI engineers that this is one of the stumbling blocks for iSCSI adoption. The good news is things in this industry happen FAST!
Vendors are now coming to market with iSCSI adapters that eliminate this problem. See: http://wwwip.emulex.com/ip/products/gn9000SI.html for one such adapter.
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This was first published in September 2001