Last Tuesday, IBM made its grand entrance into the blade server market by announcing BladeCenter, a modular system that can pack up to 168 Intel Xeon processors into a single 19-inch rack. BladeCenter and similar products will dramatically reduce IT costs for companies that own hundreds of Intel servers. However, it will be much harder for server vendors to build a financial justification for the current generation of blades among mid-market organizations.
Blade servers represent the IT industry's latest effort to pack the greatest performance into the smallest space at the lowest possible price. Unlike traditional rack-mounted servers, in which each server chassis contains a single motherboard, blade servers use a chassis that supports multiple motherboards, otherwise known as "blades." Each blade houses one or more processors, an integrated network controller and, in many cases, one or two disk drives. The chassis that houses the blades provides everything else. This includes power supplies, cooling, network attachment, media bays, and a single console and keyboard to manage all the blades in the chassis.
By sharing these components across a larger number of processors, blade server vendors can squeeze more CPUs and processor performance into a rack than traditional rack-mounted servers can. This same sharing allows blade servers to consume less power, air conditioning, and floor space on a per-processor basis. Blade servers can also (at least in theory) sell at a lower price per unit of performance because of component sharing. As we shall learn later, however, those lower prices are not yet materializing in many cases.
Blade servers come from several vendors in many configurations. They vary widely in the number of CPUs that they can fit into a standard 42U rack space. On the low end, the Dell PowerEdge 1655MC houses 84 CPUs per rack. On the high end, RLX Technologies offers models that can pack up to 336 CPUs per rack. RLX achieves this density by using relatively slow Transmeta Crusoe processors that consume less power and generate less heat than other CPUs. By contrast, other blade server vendors use faster, hotter Intel Pentium III chips. In either case, most blades house one or two processors. This makes them suitable for front-end tasks such as Web serving, mail serving, firewalls, and DNS serving.
IBM's BladeCenter takes the "faster and hotter" approach when it comes to processor packaging. Like most blade servers, it supports Windows, Linux, and Novell operating systems. However, it distinguishes itself from the rest of the blade server pack in the following respects:
- Intel Xeon processors--BladeCenter is the first blade server I know of that runs on Xeon processors rather than the slower Pentium III. A single 7U-high BladeCenter chassis can house 14 blades, each containing one or two Xeons running at either 2.0 or 2.4 GHz with up to 8 GB of ECC chipkill memory. Up to 168 of these CPUs can fit in a single 42U rack--twice as many as are possible using traditional rack-mounted servers. By using the faster Xeons, BladeCenter can offer adequate scalability not only to serve Web pages or emails, but also to support Web application servers and collaborative computing solutions such as Domino.
- Superior reliability, availability, and serviceability (RAS)--Like most of IBM's Intel servers, BladeCenter exceeds the competition in the RAS arena. The BladeCenter chassis offers fully redundant power, cooling, and network connections. The system provides nearly instant failover capabilities for almost every device. If a blade requires technical service, lightpath diagnostics identify the failed component.
- Integrated Gigabit Ethernet switch--IBM offers an inexpensive Gigabit Ethernet switch that resides in the BladeCenter chassis and that customers can manage along with processor blades from a single console. Other blade servers require external switches with their own management consoles.
These technical refinements allow BladeCenter to offer high levels of performance per square foot while also meeting the scalability and reliability requirements of most enterprises. While many blade servers have excellent performance density, they will not match up to BladeCenter on the scalability or reliability fronts. This is one reason why Intel has formed an alliance with IBM under which the two vendors will codevelop and license blade server technologies to other vendors. Clearly, Intel sees IBM as a leader in this emerging market.
Blade servers have the potential to dramatically change the way vendors architect servers, not to mention how customers deploy and use them. Adding computing capacity or reconfiguring that capacity to handle different tasks could become as quick and easy as sliding blades in and out of chassis slots, then replicating a system image to the redeployed blades. Blade servers could also spur another wave of server consolidation as customers seek to reduce power, cooling, space, and IT management costs. However, mid-market organizations should take a long, hard look at the new technology before they make any commitments. I'll explain why in next week's issue, so stay tuned.