[This is preliminary documentation and subject to change]

# Tools Used to Monitor Performance

Monitoring your server is a crucial part of server administration. By using appropriate monitoring tools, you can detect server problems, evaluate the results of changes to your Web site content, and plan upgrades to make your sites more accessible to users. The appropriate monitoring tool and method depends on the information you need.

You can also monitor your server by examining logs generated by IIS. These logs extend beyond those generated by Windows Whistler. For information about logging, see Logging Site Activity.

The following monitoring tools can provide both moment-to-moment and summary information:

- System Monitor
- Performance Logs and Alerts
- Event Viewer
- Task Manager
- Network Monitor
- Microsoft Web Application Stress Tool (WAST)
- Application Center Test (ACT)

## System Monitor

The Windows performance monitoring tool, System Monitor (formerly known as Performance Monitor) is an MMC snap-in that you can use to monitor your server's activity and summarize its performance at selected intervals. With this tool, you can display performance data in real-time charts or reports, collect data in files, and generate alerts when critical events occur. The data can be used to determine the cause of system bottlenecks and to fine-tune system and application performance.

System Monitor examines the output of performance counters. Performance counters monitor the activity of specific performance objects. In other words, performance counters monitor specific services or mechanisms controlling server resources. For example, if you click the Add button (the plus sign) on the System Monitor toolbar, you can view a list of performance object from the Performance Object drop-down list. Select the Processor object to view a list of corresponding counters, like the % Processor Time counter. From this window, you can add or remove counters to the graphic display of System Monitor, or you can configure the counters to log in a particular way. Numerous counters running at the same time can cause a small decrease in performance, so be selective.

Windows Whistler includes hundreds of counters. IIS installs its own counters, including Web service, Web service cache, FTP service, and Active Server Pages. The Web and FTP service counters and Active Server Pages object counters monitor connection activity for scripts. Counters typically measure in terms of how much, how many, or how long. Keep this in mind when selecting what counters you want to display. For a detailed list of counters related to performance, see the Counters Reference.

System Monitor is designed to provide both short-term and long-term information about the load on your server and sites. The following table lists some useful counters and provides ideal average values for each counter. The System Monitor graph plots on a scale of zero to 100 (by default), so it may be necessary to change the scale for individual counters that register small values.

Object\Counter | Ideal Value
--- | ---
Memory\Pages/sec | 0-20 (if over 80, indicates trouble).
Memory\Available Bytes | At least 20 MB.
Memory\Committed Bytes | Not more than about 75 percent of physical memory size.
Memory\Pool Nonpaged Bytes | Steady (slow rise may indicate a memory leak).
Processor\% Processor Time | Less than 75 percent.
Processor\System Processor Queue Length | 4 or less.
(Logical or Physical) Disk\ % Disk Time | As low as possible.
(Logical or Physical) Disk\ Avg. Disk Queue Length | Less than 4.
(Logical or Physical) Disk\ Avg Disk Bytes/Transfer | As high as possible.
System\Context Switches/sec | Monitor to make certain this number is low (relative to the number of system calls/sec)
System\System Calls/sec | As low as possible.
Web Service\Bytes Total/sec | As high as possible.
Web Service Cache\File Cache Hits % | As high as possible (static content). Note This value could be low if the Kernel URI Cache Hits % is high.
Web Service Cache\Kernel: URI Cache Flushes | Monitor to make certain this number is low (relative to the number of requests)
Web Service Cache\Kernel: URI Cache Misses | As low as possible.
Web Service Cache\Kernel: URI Cache Hits % | As high as possible (static content).
Active Server Pages\Request Wait Time | As low as possible.
Active Server Pages\Requests Queued | As low as possible.
Active Server Pages\Transactions/sec | As high as possible. Note ASP transactions degrade overall server performance because each transaction requires a trip to a database. If you are concerned with performance on your machine, use ASP transactions sparingly.

For more information about this tool, see the Windows Whistler online Help.

## Performance Logs and Alerts

Performance Logs and Alerts contains features for logging counter and event trace data and for generating performance alerts. With counter logs, you can record data about hardware usage and the activity of system services from local or remote computers. Logging can occur manually on demand or automatically based on a user-defined schedule. Continuous logging, subject to file-size or duration limits, is also available. Logged data can be viewed using the System Monitor display or can be exported to spreadsheet programs or databases for analysis and report generation.

Trace logs record data as certain activity occurs, for example disk I/O or page faults. When the event occurs, the provider sends the data to the log service. For more information about this tool, see the Windows Whistler online Help.

## Event Viewer

Windows Whistler includes an event-logging service, which records events such as errors or the successful starting of a service. You can view these logs with the Event Viewer. You can also use Event Viewer to monitor system, security, and application event logs. With this information you can better understand the sequence and types of events that led up to a particular performance problem. For more information about this tool, see the Windows Whistler online Help.

## Task Manager

Task Manager can be used to view ongoing tasks and threads. It can also be used to change the assigned priority of processes. However, once the process has completed, the new priority setting is lost. CPU and memory usage can be seen in real time, but information is not saved over time. The Task Manager also includes Networking and User information. For more information about this tool, see the Windows Whistler online Help.

## Network Monitor

Network Monitor captures network traffic information and gives detailed information about the frames being sent and received. This tool can help you analyze complex patterns of network traffic. Network Monitor can help you view the header information included in HTTP and FTP requests. Generally, you need to design a capture filter, which functions like a database query and singles out a subset of the frames being transmitted. You can also use a capture trigger that responds to events on your network by initiating an action, such as starting an executable file. A "lite" version of Network Monitor ships with Windows Whistler Server. A "full" version of Network Monitor ships with Systems Management Server. For more information about this tool, see the Windows Whistler online Help.

## Microsoft Web Application Stress Tool (WAST)

The Microsoft Web Application Stress Tool (WAST) is designed to realistically simulate multiple browsers requesting pages from a Web application. WAST can be used to generate customizable loads on various Internet services. WAST does have a limitation on the number of URLs that can be stressed at one time (approximately 100). For this reason, when testing large quantities of sites, WAST may need to be used in conjunction with other tools like the Microsoft Web Capacity Analysis Tool (WCAT). The Web Application Stress Tool is available on the Windows 2000 Resource Kit Companion CD or from the Microsoft Web Application Stress Tool site http://webtool.rte.microsoft.com/. Microsoft.com also houses information on testing tools, including scenarios and results. For more information, see Performance Testing with the Web Application Stress Tool

## Application Center Test (ACT)

Microsoft Application Center Enterprise Edition ships with a variety of high-end server monitoring tools like Application Center Test (ACT).

Related Topics

- For more information about Performance Testing, see About Performance Tuning.
- For more information about Scalability Testing, see Scalability Testing.

© 1997-2001 Microsoft Corporation. All rights reserved.