Learn the basics behind this hot new industry designed to (among other things) reduce the heat inherent to high-density server farms.
High Density Computing Overview
For something designed to (among other things) reduce the heat inherent to high-density server farms, it is slightly ironic that server blades have become the hottest item in the server world. In the past year, this developing technology has created a strong market for itself with vendors springing up whose entire strategy evolves around a blade-based product line (as in the case of RLX and Egenera) and other vendors that have created blade-based lines of business (as is the case of a Intel and Compaq).
During the past several years, the Internet has changed the course of server usage from single, carefully placed servers (consider the history of mini- and mainframe computers) to installations of multiple servers or high-density server farms. The PC revolution has also been part of this change, which has seen many large centralized computers replaced by numerous, much less expensive servers based on PC technology.
Cost has always been a big factor in this change, but the Internet accelerated the use of multiple servers to handle the scalability, redundancy, reliability, and performance that heavily trafficked Web sites require.
Today, many organizations find the concepts behind using large numbers of servers compelling even while finding the reality difficult. Amassing servers has a physical aspect wherein a lack of space, high heat, and complex cabling are serious problems. Then too, there are problems associated with securing, managing, and coordinating a large number of servers.
All of which, of course, in the end adds up to cost.
Rack 'em Up
The now-familiar process of rack-mounting servers was the first and most common approach to assembling large numbers of servers. Server blades are a conceptual evolution of rack-mounting, although technically they are an outgrowth of switching technology where "blades" have been used for quite some time. Using a variety of uncommon designs, for example vertical mounting and ultra-thin profiles (usually without disk storage), server blades can take advantage of low-power, low-heat operation to cram more than 300 blades into a single rack.
Each server blade is an inclusive computer system, with processor, memory, network connections, and associated electronics on a single motherboard. Most server blades do not include onboard storage (other than RAM), and they share storage units along with power supply, cooling, and cabling within a rack.
Although experiences will vary, it's expected that the repackaging of server farms into blade racks can save an organization between $500,000 and $1 million per rack -- no small incentive for an enterprise investigating investing in this emerging technology.
A Full Market
The incentive for vendors to produce server blades and systems has resulted in a market that had few entrants only a year ago but now reads like a veritable who's who in the computer hardware industry. Vendors in the blade market at press time that have announced or intend to announce products include Amphus, Centauri NetSystems, Compaq, Dell, Egenera, Hewlett-Packard, IBM, OmniCluster, Racemi, RealScale Technologies, RLX, and Sun Microsystems. Other companies that have popped up in this sector in recent months include Coventive Technology, LogiCerv Technology, Newisys, Nexcom, and Rauch Medien. We have no doubt there will be more.
All this activity is very good news for enterprises on the buy side. With competition comes innovation, competitive pricing, clever packaging of services, software development, and other advantages.
Most vendors are targeting their server blade offerings at enterprise-level data centers to solve (variously) power consumption, density, provisioning, or management problems. Of course, as the number of vendors increases and the differentiation grows, it will become more important for prospective buyers to carefully fit server blade characteristics to their needs.
Check Out the Racks
In a server blade approach, the rack is best place to start when comparing systems. Although a company will buy far fewer racks than blades, the rack is the fundamental framework, and its physical properties say much about the operation and benefits of the system designed for it.
For example, consider the system offered by Egenera: The basic rack consists of a 24 x 30 x 84 inch chassis that can hold up to 24 two-way or four-way processing blades. Egenera also offers storage, integrated switches, controllers, and cluster connection buses. The company considers its blade system a suite of processor, storage, and network capabilities in a rack. BladeFrame is tied together with Egenera's own Processing-Area Network (PAN) manager software that lets the system administrator configure, control, and monitor the blades from a single location. The system is priced starting at about $250,000.
When checking out the racks, key things to look for are rack size, density (the number of blades supported), power consumption per loaded rack, heat generated, cooling facilities, cable connections, switching options, and system coordination features to distinguish products. One important caveat: In most cases the match of blade and rack is proprietary. Thus, it is rare to be able to operate one company's blade in another company's rack.
Obviously, this makes choice of rack and vendor a long-term commitment.
Even more so than is the case with traditional servers, server blades will be designed for target applications. Some will be aimed at "general" use, typically as Web servers. These will often be of the edge server type, supporting many blades vertically mounted in a densely packed configuration.
RLX Technologies, for example, recently introduced its System 324 server blade unit that gives customers the option of running up to 336 blades in a single rack. Because of the temperatures in these tightly packed systems, there is considerable competition in the selection of processors (e.g., Transmeta Caruso and Intel Itanium) to minimize power consumption and heat.
Others blades may be application servers, usually SMP controlled with large memory resources and many storage options. Racemi offers an example of this kind of blade: The Racemi Race5 blades are server-grade single board computers that use 1 GHz Pentium III chips and support five individual, hot-swappable blades in a rack. The system runs software in a distributed fashion across the rack in a way that makes it easier for administrators to allocate resources to applications.
Still other blades will focus on network and communications functions and offer features like PCI compliance and NEBS support. No doubt vendors will come up with their own designations for use, and enterprises will have to sort through the descriptions and marketing hype to find a good match.
Software on the Edge of the Blades
For the most part, blade manufacturers have attempted to use standard software, especially operating systems, without making major modifications. This will change as competition and the pressure to diversify lead to the development of customized and third-party software that enhances various characteristics of the blades. The way that systems are managed and monitored will also become especially important.
Another potential development, and one that is unusual in the current server hardware market, is the formation of alliances between blade manufacturers and software suppliers to optimize performance and features for areas such as database management, telecommunications, application servers, and Web services. In the future, software considerations may become of greater importance to the value of blade systems than basic hardware.
Now and in the Future
Server blade manufacturers have not been immune to the downturn in the economy and the resulting decline in server sales. However, their recovery is predicted to be rapid both because of the advantages that server blades offer and because their approach is new. The savings offered by blades -- especially when appropriately matched with a user's needs -- are substantial and go beyond the direct hardware benefits. The "Big Ms" of server farms: monitoring, management, and maintenance can be greatly simplified (read: need fewer people) by using server blade systems.
That's one of the main reasons why big companies like Hewlett-Packard and Compaq will be jumping into the server blade market in the fourth quarter of 2001. It's also why many believe that within three to five years this technology and approach to packaging server power will be the mainstay of server sales.