Silverback Makes iSCSI Howl

Storage processor startup Silverback Systems Inc. claims its iSCSI acceleration chip delivers 92,000 I/O operations per second (IOPS) through a single Gigabit Ethernet port -- another positive proof point for the emerging IP storage technology (see Silverback Claims 92,000 IOPS).

If Silverback number's check out, its chip would put iSCSI on a par with Fibre Channel in terms of raw performance. Silverback's chip handles processing-intensive tasks involved in transmitting storage over TCP/IP networks, including upper-layer protocols like iSCSI.

"We think this level of performance will move iSCSI to the next level," says Ron Kroesen, VP of marketing and sales at Silverback.

At 92,000 IOPS, a standard industry measure of data throughput, Silverback's chip would actually exceed the top end of the Fibre Channel performance spectrum. QLogic Corp. (Nasdaq: QLGC), for example, says the latest generation of its dual-port 2-Gbit/s Fibre Channel single-chip controllers, the ISP2332, is able to handle 160,000 IOPS, or 80,000 IOPS per port (see QLogic Touts Next-Gen Controller).

Silverback's news comes amid a groundswell of iSCSI activity. The Internet Engineering Task Force (IETF) last month officially ratified the first version of the spec, which had been three years in the works. Shortly thereafter, Network Appliance Inc. (Nasdaq: NTAP) announced a free iSCSI software option for its storage systems; and Microsoft Corp. (Nasdaq: MSFT) has set a June delivery date for its Windows iSCSI drivers (see Microsoft to Unleash iSCSI).However, we should point out that Silverback's test bed was what the industry terms a "racing configuration": It wasn't a real-world setup.

For example, the test servers weren't accessing disk storage. Silverback set up the test to access RAM (random access memory), "so that we were measuring the performance of the networking, not the disk," says Mike Strickland, the company's director of product marketing. He adds that the benchmark "is actually quite representative of what a storage product would see for cached reads and writes."

Silverback tested its iSNAP 2100 chip using Iometer, a data throughput measurement tool developed by Intel Corp. (Nasdaq: INTC), with 512-byte block sizes. It set up four Windows 2000 servers running the beta version of Microsoft's iSCSI initiator, connected via Gigabit Ethernet to a Linux-based PC with a 2.4GHz Intel Xeon processor that acted as the iSCSI target. All servers used ServerWorks Corp. Gigabit Ethernet chipsets.

The company claims it was unable to measure CPU utilization because it hasn't been able to get Iometer to work with its Linux initiator. In the coming weeks, Silverback says, it plans to be able to measure the CPU utilization of a system running its chip; Strickland says he expects it to be somewhere around "10 percent or less" using 8K block sizes.

The iSNAP 2100 is a single-chip implementation that has dual Gigabit Media Independent Interfaces (GMIIs) and a PCI-X port. It includes external memory, which is "typically no more than 24 Mbytes" of external DRAM. So far, the company has developed only a Linux driver but claims it can port to any operating system.Silverback says the chip is priced at around $75 per port, to be in line with Fibre Channel. Wait a minute here -- wasn't one of the key advantages of iSCSI supposed to be that it's cheaper than FC?

"We think iSCSI will ultimately have higher volume and lower cost structures than Fibre Channel," Kroesen says. In the meantime, he says, "the value proposition of iSCSI is the ability to leverage the existing infrastructure... The total solution and TCO [total cost of ownership] will be substantially less in an iSCSI implementation." Oh.

As far as customers, Silverback maintains it has already lined up some OEMs -- on both the host side and the target side -- which are aiming at the second half of 2003 for their first iSCSI product shipments, according to Kroesen. Unfortunately, Silverback couldn't tell us who these OEMs are yet. Interestingly, much of Silverback's development team, based in Rochester, Minn., hails from IBM Corp. (NYSE: IBM). Could Big Blue be working up a Silverback-based iSCSI system? Neither company would comment.

The TCP Offload Engine (TOE) segment is definitely a crowded one, and Silverback is hoping its performance results will help it stand out. Vendors developing components or cards in this area include Adaptec Inc. (Nasdaq: ADPT), Agilent Technologies Inc. (NYSE: A), Alacritech Inc., Astute Networks Inc., Intel Corp. (Nasdaq: INTC), iReady Corp., Trebia Networks Inc., and QLogic (see Trebia Ousts CEO, QLogic Does Storage Trois, Will Offload Chips Be Uploaded?, Vendors Chip Into IP Storage, Intel Wiggles Its TOE, and IReady Is on Its TOEs).

Silverback, founded in July 2000 and based in Campbell, Calif., has raised $17.3 million to date, and it's planning to announce its next round of funding next week. Investors include Gemini Israel Fund, JP Morgan Partners, Newbury Ventures, Pitango Venture Capital, and U.S. Trust Private Equity Capital (see Silverback Emerges From the Mist).— Todd Spangler, US Editor, Byte and Switch