He now has continuous backup of a data warehouse, ADP payroll, and a fleet-maintenance system. “We have a lot of Novell, but that is still on Fibre Channel,” Brinegar says. “NetWare 5.1 just does not like iSCSI. When we upgrade to 6.5, we will probably convert that to iSCSI as well.”
“This [iSCSI] really changed the way we do things. Before, we had a separate tape drive for every server. My life is a whole lot easier now,” Brinegar says.
The need for speed
At the high end, Fibre Channel is still SAN king, and speed is obviously one of the main reasons. Affordable Ethernet is still pretty much a one-gig horse, whereas Fibre Channel runs at four gig, with eight on the way.
There are ways to squeeze more performance out of iSCSI. Intelenet’s Stein, for example, plugs iSCSI HBAs from QLogic into his servers. This is one of the technologies that got “flatter,” in his opinion, making iSCSI both fast and cheap enough to move his datacenter from DAS to SAN.
“You can enhance iSCSI with HBAs,” Reeves says. “You can also add, on the target side, TOE (TCP offload engine) cards or DMA (direct memory access) cards. On the initiator side, you can get NICs with iSCSI initiators built in.”
Anderson of Emergent Networks chose to use QLogic iSCSI HBAs for the engagement with Chief Manufacturing. “We could have stuck with the Ethernet ports, and Microsoft’s iSCSI Initiator [the QLogic HBAs come with a separate iSCSI Initiator],” he says, “but we went this route in order to offload the TCP/IP from the processor onto the iSCSI cards.”
Now, Anderson is not sure the performance boost from that is worth the extra expense and hassle. “Some of the Ethernet cards from Intel and Broadcom now come with TCP/IP offload cards, so, in my opinion, the lines between iSCSI HBAs and standard Ethernet interfaces are blurring.”
Meanwhile there is no doubt that cheaper 10GbE (10 Gigabit Ethernet) is on the way, and iSCSI is one of the drivers. In January, Bell Micro, a distributor of storage and computing technologies, signed a distribution agreement with Chelsio, a provider of 10GbE Ethernet adapters and ASIC solutions. Also in January, Brocade Communications bought Silverback Systems, a company that makes network processors to help to accelerate the speed and performance of storage traffic in networked storage environments. Brocade cited Silverback’s technology and expertise in iSCSI as a main reason for the acquisition.
Stephanie Balaouras, analyst with Forrester Research, thinks all this 10GbE action will make the SAN market very interesting. “It [10GbE] is too expensive right now,” she says. “I expect the cost to come down to affordable levels in three to four years.”
Don’t, however, expect to see Fibre Channel beat a hasty retreat. “Storage buyers tend to be the most conservative,” Balaouras says, “so even if iSCSI is competitive in price and performance, you won’t see people ripping out their Fibre Channel.”
And Reeves says there are other issues. “Don’t forget that the high-end storage arrays are still built for Fibre Channel. Sure, EMC says they support iSCSI on their Symmetrix line, but this is essentially an add-on. I think these vendors will eventually embrace iSCSI, but they are going to protect their high profit margins on expensive Fibre Channel equipment for as long as they can.”