Windows NT Boasts Scalability Gains

IT managers in the know have more often than not absorbed Microsoft Corp.’s rhetoric and posturing in the area of scalability with more a capsule of valium than a proverbial grain of salt. That said, the Redmond, Wash.-based software giant’s Windows NT operating system has admittedly demonstrated substantive scalability improvements since the release of Windows NT 4.0 in November 1996. But to what extent has the Windows NT operating system made good on the bluster and self-aggrandizing rhetoric of its enthusiastic creator? To what extent is Windows NT truly scalable?

In the early months of 1998, Microsoft trumpeted NT’s scalability as a well-nigh achieved reality with the availability of eight-way Windows NT servers from high-volume OEMs such as Hewlett-Packard Co. and Data General Corp. (DG, Westboro, Mass., In March 1998, for example, an AviiON AV8600 from Data General scored then record results of 16,101.27 tpmC @ $56 per tmpC in the industry-standard TPCC benchmark of the Transaction Processing Performance Council ( Hewlett-Packard later bested DG’s mark by announcing that its HP NetServer Lxr Pro 8, an Intel-based PC server leveraging eight Pentium Pro 200-MHz processors, wracked up 16,257 tpmC @ $34 per tpmC.

The performance of these eight-way machines also served at the same time to highlight Windows NT’s inadequacies with regard to scalability in greater-than-four-way SMP configurations. High-end RISC/UNIX and AS/400 platforms typically offer a scalability gradient in the neighborhood of 1.8 to 1.9 times that of an SMP base, for example. With this in mind, HP's NetServer LXr Pro8 achieved a scalability gradient of 1.55 over that of a base HP NetServer LX Pro with four 200-MHz Pentium Pro processors.

James Gruener, a senior analyst with Boston-based consultancy Aberdeen Group ( summed it up best. "[These results] certainly show that you can scale [on Windows NT]," Gruener indicated. "The problem is that however much scalability you have is still not anywhere near where it should be in a linear sense."

The release of the long-awaited Xeon processor from Intel Corp. has done much to turn the scalability tide, however. Performance numbers released by the Transaction Processing Performance Council (TPC,, for example, show four-way Xeon-based systems performing nearly 26 percent better than eight-way Pentium Pro-based systems in the TPC’s standard TPC-C benchmark test. Accordingly, an HP NetServer LXr 8000 with four 400-MHz Xeon processors notched a TPC-C benchmark score of 20,433.93 tpmC, with a cost of $30 per tpmC. Even more impressive, perhaps, is the fact that the four-way Xeon-based HP NetServer LXr 8000 demonstrated a scalability improvement of nearly 95 percent over the four-way Pentium Pro-based HP NetServer LX Pro (c/s), which notched a 10505 tpmC @ $35 per tpmC.

For the first time, then, Intel-based systems are beginning to compete on a quasi-level footing with their more expensive RISC/UNIX brethren. With Intel-based Windows NT systems pushing into the 20,000+ TPC/C score ranges traditionally reserved only for ultra-expensive high-end RISC/UNIX machines, many analysts and industry watchers suspect that it will only be a matter of time before Windows NT is accorded its scalability dues.

At the same time, however, problem areas remain.

One such problem area is that of server consolidation, a hot trend in many IT departments these days. RISC/UNIX and AS/400 managers are accustomed to consolidating a number of services or applications on a single UNIX or AS/400 box, with little or no degradation in application performance or availability. Such is not the case in the world of Windows NT, however, where specific applications are often deployed on individual Windows NT servers, resulting in greater complexity and a greater management burden for IT. According to Aberdeen’s Gruener, both Microsoft and OEMs must work to transmute Windows NT’s ostensible scalability gains into tangible benefits for customers, such as the ability to consolidate multiple applications on individual Windows NT boxes.

Other problem areas include clustering – for both availability and scalability – availability, reliability and manageability, all bedrock elements of the RISC/UNIX and AS/400 experiences and all as yet untrod ground in the Windows NT world.