Performance monitoring methodology
This tip, excerpted from InformIT, discusses some basic information about performance monitoring for Windows based computers. While it's basic, it's a good idea, from time to time, to refamiliarize ourselves with the things that we may have forgotten, in the press of events.
To monitor performance, you need to have a baseline of information. This baseline should be compiled over time and should be used for measuring any significant changes to your system. A nagging question that may have occurred to you is, By measuring performance, am I not actually decreasing it? And the definitive answer is, Sometimes. In some cases, performance monitoring may present a significant drain on resources. For example, the Windows NT Performance Monitor application itself uses CPU time, memory, and display resources. On modern systems, however, this drain is negligible. In this chapter, I note where significant performance reductions may occur. Whether you are running the Performance Monitor application or not, Windows NT automatically keeps track of performance data for tuning itself. Therefore, it does not matter if you measure 100 different parameters or only 1. The impact of running Performance Monitor also remains constant for most types of monitoring, so you need not worry about it as long as you consistently use the same tool to measure performance.
When you're monitoring performance, it is always a good idea to make only one change at a time. This way, you can measure the effects of modifying a single parameter. Also, if performance decreases or other problems come up, you'll know what to change to return to the original configuration. Documenting performance values is just as important as making changes.
The Performance Monitor includes many counters and objects with which you can monitor certain aspects of system performance. Counters are general aspects of the system that can be monitored (for example, memory, processor). Objects are the actual details you wish to track for the selected object (for example, bytes committed, processor utilization). To add a counter to the default view, click on the Add button and view the various options. In the Add dialog box, you can click on the Explain button for more information about each option.
Microsoft ships Windows NT with basic performance counters enabled. For most systems administrators, these defaults are sufficient. If you require more specific information, however, you can also enable other counters and objects. For example, to measure disk performance, you need to specifically turn on disk performance logging. To do so, you must go to a command prompt and type diskperf -ye (the y flag activates disk performance monitoring, and the e flag specifies performance monitoring for stripe set volumes). This change takes effect the next time you restart the system. Why isn't this option enabled by default? Well, keeping track of disk performance information creates a slight decrease in performance (Microsoft estimates less than 5% in most cases). Whether this slowdown is worth the additional information depends on your environment and the use of the server. To monitor various network performance values, you also need to add the Simple Network Management Protocol (SNMP) service and the Network Monitor Agent in the Network Control Panel applet.
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This was first published in September 2001