With 512 Atom processors in a 10u rack mounted unit, SeaMicro is defying not just conventional wisdom of what makes a Web server, but server design as well. Thanks to clever engineering, the company has fit eight server processors into a card smaller than a sheet of paper and hundreds of chips into a space usually occupied by less than a dozen.
Startup SeaMicro says Intel’s Atom processor, widely used in netbook computers, has more than enough juice to power Web servers serving up HTML pages.
The company is coming out of stealth mode to launch its SM10000 server which it claims will reduce power consumption by 75 percent compared to an Intel Xeon-based server of equal computing power thanks to its very low power draw.
SeaMicro said its targeting the SM10000 at the Web server market where the main requirement is the server pumps out PHP and HTML pages and processing power is not that vital.
If you want to run an Oracle database or an OLTP server, then stick to a Xeon machine. But if you want to just serve up pages, “your calculator can do that,” said CEO Andrew Feldman. “You don’t need aggressive branch prediction and all these tricks that the microprocessor industry has brought in to wring additional performance out of processors.”
SeaMicro’s CTO is Gary Lauterbach, the chief microprocessor architect for Sun Microsystems UltraSparc III and IV and also AMD’s Bulldozer architecture. Feldman said Lauterbach felt he was being asked to make tradeoffs for single-threaded performance at the expense of too much power in his designs.
When Lauterbach saw the workload that was coming to dominate the Internet was small, simple workloads that don’t need high single-thread performance, he came to believe that too much power was being thrown at a small problem. Server processors had all kinds of complexity, with things like out-of-order processing, aggressive prefetch and branch predictions, which create overhead and draw power even though many tasks, like Web serving, don’t need that much complexity in the CPU.
“So his insight is there are smaller, more efficient CPUs that if tied together more efficiently could outperform large CPUs on the basis of performance per unit power,” Feldman told InternetNews.com. “Virtualization is proof CPUs are the wrong size. A virtual machine’s job is to carve your CPU up into smaller CPUs. We say why not just buy smaller CPUs?”
SeaMicro evaluated the ARM processor, the Atom’s biggest competitor, but the company found the Atom had higher performance per watt.
The Secret Sauce, a Redesigned Motherboard
In addition to the Atom, SeaMicro redesigned the motherboard entirely. Blades, the popular form factor for servers, stretch 20 to 30 inches deep and are a foot wide, much of it the motherboard, and they hold just two or four Xeons. Thanks to a redesign of the motherboard, SeaMicro can create boards that are only five by 11 inches that hold eight Atom processors and memory.
This secret sauce of the SM10000 is what allows the boards to be so small. The company was able to remove things like the I/O assembly, BIOS , the networking interface and hard disk controllers. There are basically only three chips on a SM10000 card: the Atom CPU, DRAM, and the custom chip SeaMicro designed to replace all the old processors.
Feldman said the custom chip is not exclusive to the Atom and could conceivably work with Intel’s Xeon processors. Intel (NASDAQ: INTC) will have to license the technology, though; SeaMicro has patents for its secret sauce.
With these multi-CPU cards, SeaMicro built a fabric to link hundreds of the motherboards together inside the 10u chassis. SeaMicro added gigabit switches, a load balancer and a terminal balancer, all in hardware. The Linux/Apache/MySQL/PHP software of the popular LAMP stack used by Web servers that the SM10000 is optimized around, will run unmodified on the SM10000, no recompile needed. “We are a LAMP stack crushing machine,” boasted Feldman.
The 10u unit has a full power draw of two kilowatts. That’s about equal to three or four desktop PCs. The unit holds 512 Atom Z530 processors running at 1.6Ghz and 1TB of memory and has room for up to 64 SATA or SSD drives and 64 1GbE or 16 10GbE Ethernet ports. Feldman claims that under 100 percent load, and performing just Web page serving, the SM10000 is 3.2 times more power efficient than the Xeon.
Feldman admits Intel was not keen on the idea of its chip for netbooks being used in a dense cloud server. Intel has lightweight, low-usage Atom servers for the SMB market, but SeaMicro was an entirely different class of hardware.
“At first, they threw a hairball. But what we showed them was we’re not suggesting you need less computing, we’re suggesting you need the same amount of computing or more, just in smaller units,” he said.
The company argued that many firms are limited by power budgets, not hardware budgets, and if customers can get the same amount of computing for one-quarter of the power, they might sell up to four times as much silicon as before. That, he said, won Intel over.
“They’ve done a very credible job in terms of putting this all together,” said Nathan Brookwood, research fellow with Insight 64. “The only area where I think there’s a weakness in what they are doing is they lack ECC [Error Correcting Code] on the memory. Some edge of the network is handling transactions, so there is some concern. If there’s any area where they have a problem, that might be it.”
Feldman doesn’t think ECC, which is standard on a regular server, is necessary. “We haven’t seen it as a problem in the Web tier. We’re not going to the financial world. ECC is a religious debate. Our view is that the ECC corrects a host of different problems that are better corrected by good motherboard design,” he said.
Other than the memory issue, Brookwood said SeaMicro has a strong story for a large portion of the market that just needs to serve up pages.
“The aspect of this that’s compelling is if they can demonstrate the power savings, then people will be attracted to it either because they can lower their power cost. Or, they may have already maxed out on power coming into the facility and need to handle a bigger workload. Now people can add more computing for the same amount of power,” he said
The SeaMicro SM10000 will be generally available July 30, 2010 in the U.S. and some international locations. The list price for a base configuration is $139,000.