Somewhat against the industry's initial expectations, servers based on the Numa multiprocessing architecture are cutting a small but determined niche in the midrange market - so much so that manufacturers are struggling to produce machines fast enough to fulfil demand.
Last week Sequent, one of the earliest entrants into the Non-Uniform Memory Architecture market, admitted sales had so far exceeded expectations that it was experiencing delays in delivering new Numa systems while its manufacturing process tried to catch up.
The company expects to be back to delivery times of five weeks or less by Christmas but the problem is indicative of the success Numa servers are enjoying.
Around 90 per cent of Sequent's new business is now in Numa servers, and almost no new servers based on its older symmetric multiprocessing (SMP) design are being sold. The Numa design merges the most efficient features of the two traditional designs for systems with more than two CPUs - SMP and massively parallel (MPP).
The other original Numa vendor, Data General, said that at least half of its server sales to new customers are now Numa-based and it is shipping all it can build.
The bigger players have now started to emphasise their commitment to the Numa model. Hewlett-Packard, IBM, Digital, NCR, Sun Microsystems and even Silicon Graphics are all working on Numa servers to hit the market some time next year.
According to research compiled earlier this year by analysts Aberdeen Group, the ability of Numa to scale upward - given the expected increase in data warehousing performance requirements - will force all vendors to offer customers their own version of the technology.
"Aberdeen Group believes that all hardware suppliers will move towards fusion [of SMP and MPP] technology within the next two to five years. The winners will provide not just a high performance server but also the experience and insight to aid users in leveraging the new technologies most effectively," it stated.
Hewlett-Packard, for example, plans to market its V-class server line to companies that want to unload mainframes that are not Year 2000-read. It will offer Numa clustering and mainframe level partitioning of the operating system on future models.
All this focus is in contrast to the early days of the technology. Even by 1996 Numa was largely viewed as a niche or future architecture, being pursued hardest by smaller vendors desperate to get some form of technology edge to compete with their larger and more successful rivals.
The gamble seems to have paid off. For the two main vendors, Sequent and Data General, boxes are shipping out the door much faster than expected. Not only are traditional SMP server customers choosing Numa systems instead, but customers new to either company are choosing Numa for a variety of reasons.
Numa is an improvement over SMP because it allows each processor to access local memory and also share memory across a high bandwidth interconnect, though this can become considerably slower than the local memory access.
In SMP systems the completely shared memory capability causes bottlenecks on the interconnect, limiting performance and scalability. In Numa servers the interconnect is highly scaleable, eventually up to systems running more than 1,000 processors with the help of clustering.
With this scalability in mind, Numa servers are being used mainly for either data warehousing or online transaction processing, applications that can quickly increase the required workload and can be mission critical.
Sales and marketing vice president for Data General, Joel Schwartz, said many Numa machines are going to customers setting up new applications, looking for the upwards growth potential inherent with the technology.
"This industry is full of talk and does not often deliver?.but the Numa architecture is a real architecture and people see that it works and that it scales," said Schwartz.
Sequent's senior marketing manager, Steve Wanless, said his company has sold a number of Numa servers to companies taking the opportunity to buy a single-box, open systems solution to replace a number of ageing systems in one go. Shifting applications to servers can cut down the number of systems requiring support and be done in conjunction with solving Year 2000 problems.
One of the key advantages of Numa systems is that while they run Unix, NT applications can run on the same system. More importantly, moving to Numa does not require any rewriting of application code - as a shift to an MPP system would require - only minimal fine tuning for performance. It still remains to be seen whether any software vendors will rewrite applications to actually take advantage of Numa's memory use characteristics.
Numa has appealed to organisations setting up large data warehouse applications, previously the realm of MPP systems. Sainsbury's has just added a 32-processor Numa box to its existing 16-processor system to help analyse up to 3Tbytes of data being collected from its loyalty card programme. B&Q is another retailer looking to upgrade some SMP systems to Numa.
On the OLTP front, the Inland Revenue for example, decided to upgrade its Sequent SMP servers to Numa to run an Oracle database, when it became wary of attempting to run a project that size on MPP systems.
Next year, with the arrival of Intel's Deschutes processor, Numa servers should take another leap forward in performance, with new versions of the interconnect technologies in use by Data General and Sequent also expected. Both companies were given an expected to improve rating for their market position and financial performance by Gartner Group's systems survey last month.
By that time some of the big players should be announcing their own Numa products, promoting much wider acceptance. While Numa has yet to prove itself over time and a bigger variety of applications, it so far shows the potential to at least offer a decent performance for the price and a scalability that protects IT director's big server investments for some time to come.
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