Whether blade systems are a fit for a business has less to do with the kind or size of the business itself than with the organization's IT demands. If your business tends to buy one or two servers a year, justifying a blade system is difficult. If you typically purchase clusters of 4 to 12 servers, the savings in management costs and potential power consumption may make buying blades worthwhile. Since the blade system could cost more initially, an organization with a single administrator might not save enough in management costs to make up the difference.
Differences Among Blade Servers
On the market you can find a number of enterprise-oriented blade systems from vendors such as Cisco, Dell, HP, IBM, and Sun, as well as from smaller vendors such as Acma, PogoLinux, and SuperMicro. Such systems typically use differing hardware, so blades from one system cannot be used in another chassis, or even in older (or newer) versions of the same vendor's chassis. The systems also differ substantially in how they are managed, what connections they offer, and, of course, in the number of blades and processors, the maximum memory and drives per blade, and cost.
It's not necessary to spend $50,000 or more for a blade system. You can choose small, 1U, two-node systems that start at under $2000, and chassis that hold four blades with starting prices under $5000. Ordering these systems is much the same as ordering individual servers, except that you need to look closely at network and storage options to ensure that each blade has the capacity you require. Processors and memory are available in the same varieties and capacities as they are for standard servers--some blade systems even offer both Intel and AMD processors in the same chassis, as well as blades with up to four 12-core processors.
Benefits and Drawbacks
Blade servers can reduce management costs, save power, free up administrators for other tasks, simplify data-center cabling, and enable remote administration without extra equipment (such as KVM over IP switches). They also offer better reliability than individual servers, with options such as dual redundant power supplies and high-availability components.
The biggest problems blade systems may introduce are power and cooling requirements. Since blade systems can fit more CPUs, memory, and other components into smaller spaces than other systems can, they might produce more heat, and may need more power. Some blade systems can pack 672 CPUs into a standard 7-foot rack, which would require 38,400 watts of power and would produce more heat than a commercial-grade oven.
Since many blade systems are available for purchase with less than a full complement of blades, you might buy a system with a few blades and get more as required. But with hardware standards evolving so quickly, even after a period as short as 18 months the blades you purchased with the system might no longer be available. Finding out whether previous versions of blades are still supported will give you a good indication of whether new blades with faster processors and memory are likely to be compatible with the half-full chassis you already have.