Computer data centres could soon look a lot roomier as a wave of server blade products hits the market this year. Their server-on-a-card technology will not only cram more power into less space but cut the power bills of bandwidth-fillers like data centres, telcos and ISPs.
The exponential growth in internet use over the past few years has required a correspondingly rapid ramping up of computing power to service that demand. The servers needed to provide ever-multiplying millions of web pages each day can occupy large amounts of rack space at a data centre and consume huge amounts of power. But web servers have taken on the weight-watching challenge and begun to evolve into rack-mountable versions a fraction of their former bulk.
Server blades, compact servers stripped down to their most basic components — basically circuit boards with processors — using less power and taking up less space but offering more power per rack, hold the promise of easily managing huge web-serving operations. And as the technology develops, they may also eventually run back-end applications, challenge huge supercomputers and help with the promise of worldwide grid computing.
HP product manager Jeff Healey describes the front end of a modern data centre as a kind of battleground.
“On the one hand, data centre operators are contending with growing racks of front-end and utility servers, deployed to handle surging edge-of-network applications like web serving, firewalls, web and wireless content serving, DNS [domain name system] and DHC [dynamic host configuration].
“On the other hand, shrinking available floor space, high power and cooling bills and a shortage of IT personnel to manage all these resources is complicating growth. What’s more, rapid spikes and declines in computing workloads require data-centre operators to quickly re-allocate and redeploy servers. Otherwise, they have to contend with either resource shortages or underutilised assets,” he says.
Consequently, service providers and enterprises need a space-efficient and power-efficient computing infrastructure that can rapidly respond to changes in computing workloads.
Healey says blade servers can be deployed remotely and automatically configured based on their slot, bay or rack location. And servicing is as simple as “ripping and replacing” server blades without bringing down the whole system, he says.
Server on a card
But what are server blades? Gartner Asia-Pacific servers and storage research director Phil Sargeant says there is no single definition of a blade server, but generally it is a server on a card that can be plugged into a common chassis. They include a processor, memory, disk storage and network connections that allow hot-pluggable changes.
Management software helps the customer look after the multitude of servers. Blades can or will run on Windows 2000, Unix, NetWare or Linux, and have network connectibility using ethernet, iSCSI and fibre channel. Sydney-based Sargeant says the direction of the changes will mean customers with hundreds of servers can make significant savings in office and data centre space.
Blades rely on external storage systems for their data requirements, Sargeant says. “A number of blades will be installed into the blade manufacturer’s power chassis, and it is here that the shared network connections, power supplies and cooling fans are located. Generally the blades are stacked vertically within the chassis.”
Blades typically operate as multiple, unique servers, working independently of each other. Because most blade servers have just one or two processors, which are usually not deployed in a symmetric multiprocessing (SMP) configuration, the appropriate applications for server blades will be distributed front-end applications, not more demanding database applications, transaction processing or technical applications. Sargeant says a farm of blade servers, connected behind an external load balancer, can easily be used for web hosting, email, domain name servers or utilities such as intrusion.
Each blade server system has its own management software, Sargeant says.
“It is this software that allows the administrator to control hundreds of blades from a single console. The management software supports the dynamic re-allocation of blades, enabling customers to add and remove blades at will. This blade management tool is not a complete server management tool, but most blade management tools have a simple network management information base agent that enables the blades to be monitored from a third-party management product,” he says.
Savings, but limitations
IBM’s X-series sales manager, Brendan Paget, recently returned to New Zealand after spending four years in North Carolina helping to develop Big Blue’s blade servers. Wellington-based Paget describes blades as a new physical packaging technology, replacing a tangle of cables and switches, as opposed to a fixed server system. They allow for better rack utilisation and, from a company perspective, give better cost per square metre.
Traditional servers, he says, are purpose-built with no flexibility. Blade servers can be altered rather like a customisable car kit. The server blade is the engine and the infrastructure around it is the body shell, which can be adopted for a variety of uses. As can the engine, be it petrol, diesel, gas, anything. Everything is removable back or front, Paget says, allowing easier maintenance and upgrades.
“As [vendor] companies continue to sell their IT products with a lot of servers, many [users] tell us they want to centralise their servers. The blade technology is a great way to take the small servers and consolidate them into one managed area,” Paget says.
However, while all may seem fine with blade servers, there are some pitfalls. HP’s Healey warns customers must understand that these servers are designed to solve specific problems associated with general purpose server environments such as cooling and density, and there are certain types of applications that are not suited to a blade server environment.
IBM, however, sees no real disadvantages, but Paget warns some blade technology has not succeeded due to a lack of power and performance.
For Gartner though, a major concern is the lack of standards and the adoption of many form factors by the relevant blade vendors. Currently there are no uniform standards, a fact that has hindered the development of higher-density blade solutions as well as frustrated customers. Because existing designs use what is essentially a passive back plane, blade engineers are forced to host a variety of unwieldy peripheral components(disk controllers, network interfaces, I/O ports), on the blade itself.
Critics say the result is a bulky “PC on a card” solution that does little more than cram a bunch of underpowered components into an unconventional form factor. Consequently, Gartner expects a major war over standards and interoperability during the next 18 months.
Hewlett-Packard’s blade programme preaches adoption of the CompactPCI and NEBS (network enterprise building standard) standards as the basis for all server-blade architectures. Compliance of these two standards would create fully interoperable server blades from multiple vendors that can be interchanged on the fly. Meanwhile, a group of heavyweights including HP, Intel, IBM, Sun, Dell and Microsoft are championing a technology called InfiniBand as a single, unified input/output “fabric”. It would use task-specific nodes that communicate via an IP-like serial protocol.
But no InfiniBand products have yet been shipped. Gartner suggests waiting until the market is more mature before purchasing blade server products, as manufacturers are only just beginning to understand how blade servers are best deployed and used, and users are concerned over the potential lack of compatibility. But don’t wait too long. The ever-growing demand to cram servers into as small a space as possible will keep the worldwide blade server market growing from an estimated 84,810 units shipped in 2002 to more than a million shipments by 2006, Gartner said in February. And Sargeant expects server blades locally to grab 10% to 15% of the main server market, which overall is estimated globally in 2005 as $US60 billion.