There are two ways to save money in the data centre: use fewer servers or fit more servers into a smaller space. Virtual server technologies help companies make better use of existing hardware, but blade servers can pack hundreds of servers into a single 19 inch rack.
Blade servers started as a spin-off from mobile technologies, using low power processors for higher density server installations, packing a complete server into a slim unit that fits into a rack shelf. In the past year, blades have become big business, moving in from the edge of the network to host core business systems. Processors have become more powerful, and now there are Intel-based blades based on the latest high-end Xeon processors.
Traditionally seen as a tool for managing web farms, blades are now moving up into the rest of the business. While some organisations use them to run desktop operating systems, or as testing tools, others are using blades to deliver complex business applications. Fujitsu Siemens' FlexFrame for MySAP is a flexible environment built around blade servers running the SAP business suite on Linux.
More complex desktop applications can also take advantage of blade servers. Using tools such as Citrix's MetaFrame Presentation Server, applications run on relatively low cost blade hardware and are used from user desktops. Need to upgrade an application? Just install a new image on a blade, instead of traipsing around every desktop PC. Desktop clients for business critical applications like customer relations management systems will benefit from this approach, as they are large, expensive and difficult to maintain.
With Sun's FireBlade solution, organisations can mix Sparc and x86 processors in the same blade shelf to run Solaris and Linux applications. A separate server manages the blades, deploying operating systems and handling configuration. Sun sells single function server appliance blades to use as load balancers and hardware SSL accelerators to ease web farm development and deployment.
Managing blades is critically important. Blade installations need to be flexible, so organisations can take advantage of the way systems can redeploy blades on the fly. Tools such as Microsoft's Automated Deployment Services allow organisations to build server images that can be held on a central server, and then deployed in minutes to an array of blades. It's possible to build a library of different images.
This approach is used by most blade management solutions, and it saves on system administration time and resources. There are important issues, though. Blades are "headless", so they need to be controlled over the network. Good management tools are essential - large-scale management frameworks and hardware-specific applications. HP uses its Insight Manager tool to control its blades, and provide system administrators with hardware reliability information, based on built-in monitoring systems.
Intel sees two uses for blade servers. As well as being flexible servers for running web farms, larger modular installations can run complex applications. Running financial models across groups of blades means applications can treat them as flexible modules that are redeployed to target processing power where and when needed. With appropriate management tools, blades are even suitable for parallel processing applications, providing an alternative approach to scientific computing.
Enterprise blade solutions from such companies as Egenera treat blades as processing area networks. With Egenera's management application, processing, storage and network are treated as resource pools, distributed across blade hardware running Linux. These blades are diskless, using external storage like a storage area network. Egenera's management tools allocate resources to applications depending on what pools are available, and the set of business priorities.
There's one big snag. There is still no standard for blade interconnects, so Sun's blade hardware won't run in HP's shelves. Intel is pushing the InfiniBand serial interconnection technology for future blade systems, while most current blade backplanes are based around gigabit Ethernet (and proprietary connectors).
Soon, blade servers, virtual servers and component software will come together. Advanced management tools will monitor performance and redeploy servers in minutes to support changing demand, moving application elements from blade to blade, adding more resources as required. The hardware is already here; now it is time for the management tools to catch up.
