Scalability Daze

Lately, reader email has kept me thinking about scalability of both Windows NT 5.0 and hardware. I recently received an email from a reader asking about available software for a MIPS-based Windows NT Server. Apparently, this reader had seen Joel Sloss' October 1995 review of the NEC RISCServer 2200 and wondered whether it was worth the current asking price of $250 (the price when we reviewed it was $11,500). Before I could respond, the reader wrote back saying that his supervisor had decided not to buy the system.

At the same time, Digital Equipment announced it was selling the manufacturing rights for its Alpha and StrongARM chips to Intel. I started imagining future readers asking me whether a $250 dual-Alpha server was a good deal.

Before I let my mind wander too far, I did a little analysis and concluded that the Digital and Intel deal is OK for Alpha users. First, Intel joins Mitsubishi and Samsung as a Digital outsourcing partner for manufacturing the Alpha and StrongARM chips. This partnership lets Digital focus on design, while its partners focus on manufacturing. As a result, Digital can reduce its development costs and can start pricing its Alpha-based servers more like its Intel-based servers for NT.

Also, Digital, Intel, and Microsoft have agreed to cooperate on source code compatibility of NT 64-bit APIs across Intel's IA-64 (code-named Merced) and Digital's Alpha. This cooperation means software developers will be able to write code once and compile it to run on either Alpha or IA-64.

In past editorials, I mentioned 64-bit NT 5.0. Technically, that term is incorrect. NT 5.0 is still a 32-bit operating system, but NT 5.0 will incorporate a 64-bit Very Large Memory (VLM) model capability, initially for Alpha only. By using Microsoft's 64-bit APIs to take advantage of this VLM, enterprise-level versions of SQL Server, Oracle, and other applications can increase performance when a server has more than 4GB of memory (although the additional memory addressable through the 64-bit APIs is not pageable or swapable). NT 4.0 applications are limited to 2GB of RAM, and NT 4.0 Enterprise Edition applications are limited to 3GB of RAM. VLM uses 4GB to 32GB of RAM.

By addressing more memory, applications can keep more data in the computer's memory simultaneously, reducing the need for swapping data to and from a disk. Digital claims that Oracle running on VLM can run 50 times as fast as a similarly configured system without VLM.

Getting back to my previous editorials that deal with 64-bit NT 5.0: My point was that the Alpha-based systems will have a significant head start on providing a platform for applications to take advantage of these VLM APIs. For companies that are bumping up against the performance ceiling, the 64-bit VLM capability is welcome news.

Scaling the Performance Wall
Scalability, performance, server consolidation, and application distribution have been issues as long as I've been working in MIS. For example, when I started with Duke Communications International, I remember having to buy an additional IBM System/38 because the existing system hit a performance wall. That addition meant all kinds of fancy programming and application distribution as my MIS department tried to make the two systems work as one. Eventually, we were able to consolidate everything into a much larger AS/400--scrapping all the programming we did to tie the S/38s together. Now, 10 years later, the NT community is reliving the struggle with all of those issues.

In the December 1997 WebDev column, "Testing Your Web Environment," Windows NT Magazine's Web master, T.J. Harty, concluded that running a Web server on two dual-Pentium servers provided better performance than running a Web server on one 4-way system. On the 4-way system, SQL Server and Internet Information Server (IIS) were competing with each other for resources. IIS bandwidth maxed out on the 4-way long before the CPU reached its performance ceiling. So now T.J. runs SQL Server on one system, IIS on another system, and Cold Fusion-based forums on yet another server. Even though the Web site has a 4-way system, T.J. chooses to use multiple servers.

How should you feel about the introduction of 8-way NT-based systems? Before you buy one of these systems, do yourself a favor and test it thoroughly. The Windows NT Magazine Lab has scheduled several tests of 8-way NT-based systems. The Lab will test SQL Server Enterprise Edition on an 8-way, Oracle Enterprise Edition on an 8-way, and Oracle VLM and SQL 7.0 on an Alpha system with lots of RAM. Finally, the lab will test the difference between running multiple BackOffice products on an 8-way system versus running them on separate NT servers. These projects are big, but I know many of you are already trying to scale the performance wall and need answers. If you want to suggest performance and scalability tests you would like to see in Windows NT Magazine, drop me an email.

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