The "service" part of being an application service provider (ASP) includes servers—a lot of them. A lot of servers translates to needing a lot of room (even with rack-mounted servers), cooling, and power. Intel, IBM, and Compaq are working on "ultradense" servers that will let companies cram more computing horsepower into each rack of servers without taxing power supplies and air-conditioning systems.
In the past, server designers focused primarily on boosting the power of single servers and making them more reliable. But with the Internet's growth, many companies have decided to fill racks with dozens of less powerful machines to accommodate immense amounts of traffic.
The argument for having many small servers instead of fewer large ones isn't new and makes good sense. First, CPU speed is only one of the bottlenecks for server performance. Available memory, network bandwidth (both on the wire and on the network card), and disk I/O can also create a crunch on any kind of shared server such as a Web server or application server. More servers mean more memory, more disk I/O paths (even if you use SCSI you still have to time share), and more network I/O room. Second, according to Microsoft and in my experience, Windows 2000 performs better on two two-way servers than on one four-way server. Third, having more servers means that if one of those servers goes offline, you lose a smaller percent of your total computing power until it's back up or you replace it.
Several companies already sell servers that are 1.75 inches thick, a measurement known as 1U. A rack can hold 42 horizontally stacked 1U servers. In the future a rack the same size will be able to hold hundreds of ultradense servers—essentially exposed motherboards stacked vertically in groups inside enclosures several Us high. IBM's Intel server group plans to use this configuration to achieve the power of two to eight servers per U.
Whether you classify them as ultradense or skinny, the servers won't all follow the same design, and that design will evolve with time. Initially, these superskinny servers will be full-featured designs such as today's models, and server density will be the name of the game. But later, the devices will be blown apart into separate components, according to IBM and Intel, with different boxes for CPUs, storage, and network communications. The end result could look like stacked motherboards.
Superthin servers face the problem of eliminating heat. Although the servers will reportedly use comparatively low-end parts, the slender server design leaves little room for cooling fins on CPUs. The chips will have to run cool, and they'll need all the cooling help they can get, because a fist-sized heat sink such as the one on the Pentium III I'm now working on isn't an option. Network Engines, a pioneer of skinny servers, has reportedly hired a Raytheon aerospace engineer to design "heat pipes" that use evaporating alcohol to cool the new Sierra server's dual CPUs.
More density in computing allows individual computers to be less powerful. Intel, which sells chips primarily in the desktop and laptop market, is interested in the ultradense server model and plans to leverage its experience building laptops—by their nature power-saving and relatively cool—to build these ultradense servers. According to Mike Fister, general manager of Intel's enterprise platforms group, the 815EM ultradense server chipset will accommodate CPUs that need 2.56 watts of power and will accommodate up to 512MB of memory. And the 440MX chipset will work with 2.1-watt systems with up to 256MB of memory.
When will we see these servers? Mary McDowell, head of Compaq's Intel server division, expects to see the first ultradense designs in 2002. IBM expects the first designs to start arriving in September 2001, although IBM won't have them that soon.
The idea of smaller servers isn't new. In April 2000, Netier started offering thin servers to complement its line of Windows NT-based thin clients. Although the company then quietly withdrew the offer a few months later, Netier withdrew the product because the company was in financial trouble, not because the idea was bad. And Storage Area Networks (SANs) already divorce storage space from the CPUs driving them. Ultradense and ultimately compartmentalized servers—an extension of the same mindset that makes SANs work—will dominate server-based computing.