Data Centers

Got RAM?

Why would a small Win2K network run more slowly after server RAM was increased to 128 MB? TechRepublic members had several theories, but only one asked the fundamental question: Is 128 MB enough? Ed Bott shares the responses and levels a new challenge.

This week's Microsoft Challenge didn't start out as a trick question, but it ended up that way, as a seemingly straightforward request turned out to have some surprising twists. The challenge came from a TechRepublic member running a small (five workstations) Windows 2000 network, who is baffled because he's seen no improvement in performance after increasing server RAM from 64 MB to 128 MB. In fact, his network seems to be running slower than before. Where is the memory being used up? What sort of performance monitoring tools does he need to track down the problem?

Surprisingly, no one challenged one of the basic assumptions in the original question: Is 128 MB really adequate? According to Microsoft's own System Requirements page, the recommended minimum requirement for Windows 2000 Server is 256 MB of RAM. Moving from 64 MB to 128 MB brings the server up to Microsoft's minimum supported configuration. TechRepublic member DCI was the only respondent to flag this issue, pointing out that "128 MB really isn't that much of an improvement for NT server, especially if he is utilizing Active Directory and this is the only server in the forest."

A few experienced network administrators argued, correctly, that a proper diagnosis requires more information. Jamiec, for one, noted, "You first need to determine what this server's function is. It's quite possible that you have it overloaded with functions, like maybe it's the PDC, Internet Information Services, Exchange, and SQL Server all rolled up into one! That might work for such a small network, but it would be better to split the functions off to different servers."

TechRepublic member parksw asked the bottom-line question: "What performance gains is he expecting?" and then laid out a specific monitoring program to identify the bottleneck. The problem may be the disk or the CPU, which you can determine by using PerfMon to grab the following basic counters:
  • PhysicalDisk—Avg. Disk Queue Length. "If consistently high, upsize the disk subsystem."
  • Processor—% Processor Time (Total). "If consistently > 80, upgrade the CPU."
  • Server—Work Item Shortages. "If consistently increasing, it means the server is failing requests, usually CPU or memory."
  • Memory—Pages/sec and Paging File - % Usage. "If these two are always high, add memory."

Several TechRepublic members zeroed in on the Windows swap file as a possible culprit, especially because performance seemed to get worse with the RAM upgrade. Brianlusk recommended this tweak: "I would change the swap file parameters to force Windows to write a new one that reflects the added RAM. That is a usual culprit for performance hits after upgrades."

Finally, tgiboney delivered a persuasive argument for investigating disk fragmentation as a possible cause of performance problems. "Because the problem is slowly getting worse, he may want to look at disk fragmentation on the server and workstations. I have had good results with Executive Software's Diskeeper 5.0 for Win2K, running it in the off hours on my servers and workstations. The improvements are noticed by all. Read this NSTL white paper for details."

Ultimately, the network administrator who asked this question in the first place may need to go back to school for additional training or in-depth instructions on how to deal with an expanding network. Thanks to all the TechRepublic members who contributed to this week's challenge. I've awarded 2,000 TechPoints to everyone who was quoted this week.

Here's Ed's new Challenge
Windows 2000 Service Pack 1 has now been available for one month. I'm interested in hearing reviews from TechRepublic members. If you've upgraded, how did your installation go? Did you run into any bugs, gotchas, or BSODs? Would you recommend SP1 for anyone running Win2K, or should administrators install it only if they have known problems to deal with? As always, I'll pick the best answers and spotlight them in two weeks, so make sure you cite specifics and make a compelling case. If you've got links to well-hidden information about SP1, those are welcome, too. I've got 2,000 TechPoints available for the best responses. Click here to tackle this week's Microsoft Challenge.

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