Monitoring Network Performance

One way to monitor network performance is to use a stopwatch to see how long it actually takes to complete common network tasks, such as opening documents or printing reports. If you choose to monitor your network by using the stopwatch technique, you’ll want to get a clipboard, baseball cap, and gray sweat suit to complete the ensemble.

A more high-tech approach to monitoring network performance is to use a monitor program that automatically gathers network statistics for you. After you set up the monitor, it plugs away, silently spying on your network and recording what it sees in performance logs. You can then review the performance logs to see how your network is doing.

For large networks, you can purchase sophisticated monitoring programs that run on their own dedicated servers. For small- and medium-sized networks, you can probably get by with the built-in monitoring facilities that come with the network operating system. For example, the following illustration shows the Performance Monitor tool that comes with Windows Server 2003. Other operating systems come with similar tools.

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Windows Performance Monitor lets you keep track of several different aspects of system performance at once. You track each performance aspect by setting up a counter. You can choose from dozens of different counters. The following table describes some of the most commonly used counters. Note that each counter refers to a server object, such as physical disk, memory, or the processor.

Commonly Used Performance Counters
Object Counter Description
Physical Disk % Free Space The percentage of free space on the server’s physical
disks. Should be at least 15 percent.
Physical Disk Length Average Queue Indicates how many disk operations are waiting while the disk
is busy servicing other disk operations. Should be two or
fewer.
Memory Pages/second The number of pages retrieved from the virtual memory page
files per second. A typical threshold is about 2,500 pages per
second.
Processor % Processor Time Indicates the percentage of the processor’s time that
it’s busy doing work rather than sitting idle. Should be 85
percent or less.

Here are a few more things to consider about performance monitoring:

  • Performance Monitor enables you to view real-time data or to view data that you can save in a log file. Real-time data gives you an idea about what’s happening with the network at a particular moment, but the more useful information comes from the logs.

  • You can schedule logging to occur at certain times of the day and for certain intervals. For example, you may schedule the log to gather data every 15 seconds from 9:00 to 9:30 every morning and then again from 3:00 to 3:30 every afternoon.

  • Even if you don’t have a performance problem now, you should set up performance logging and let it run for a few weeks to gather baseline data. If you develop a problem, this baseline data will prove invaluable while you research the problem.

  • Don’t leave performance logging turned on all the time. Gathering performance data slows down your server. Use it only occasionally to gather baseline data or when you’re experiencing a performance problem.