• Illustration: SPA Report

A free Server Performance Advisor (SPA) diagnostic tool will help administrators monitor various Windows server resources to determine the root cause of performance problems. Administrators can specify which performance parameters are analyzed and which thresholds are considered important, but the tool still requires experience and expertise to correctly interpret the data and take the necessary corrective steps.

Measuring Performance

Developed to diagnose root causes of performance problems with Windows Server 2003, particularly in Internet Information Services (IIS) 6.0 and the Active Directory (AD) service, SPA tracks information from data collectors—performance counters and event trace information—to determine which services and subsystems, such as the file system, networking, or processor, are stressed under the workload.

Performance counters. Windows performance data is collected from counters, which expose various measures of the performance of computing resources, applications, or services. For example, the disk subsystem on a Windows server exposes counters that indicate how fast data is being transferred to and from the disk.

Trace instrumentation. Trace instrumentation uses data collected from Event Tracing for Windows (ETW, also sometimes known as Enterprise Tracing for Windows), which logs major operations, such as Hypertext Transfer Protocol (HTTP) requests from a given connection on IIS. The logged data includes the duration of the event, the processes and threads related to the event, and the user- and kernel-mode processor time used. Trace information is available for AD, file and print services, IIS, and the OS.

SPA’s logs typically record only short periods of activity measured in seconds or minutes rather than hours. SPA then analyzes the data it collects to discover the components and requests that created high loads on the system during a given collection period. By analyzing the interactions among performance, event data, and configuration information from the Registry, and comparing them with rules that describe known or possible problems, the SPA can advise administrators on steps that could resolve performance problems.

Each report includes a high-level view of performance, important data about the performance of specific objects, such as AD search requests or processor utilization, and performance advice, including any warnings about the system’s health. (For a sample report, see the illustration "SPA Report".)

SPA can not only be used to identify trouble spots and speed recovery after a server failure but it can also be used proactively in early phases of deployment to identify potential performance bottlenecks and ensure that servers are sized adequately for the expected load and client traffic. In addition, administrators can collect regular reports from production servers to learn how the servers are used and to identify irregular usage.

Availability and Resources

SPA requires the following:

• Windows Server 2003 (SPA cannot be run on Windows clients to monitor Windows servers)
• Administrator privileges on the local computer or membership in one of the following groups: NetworkService, Performance Log Users, or System
• Sufficient disk space, as SPA can use 5 to 10MB per minute when collecting workload data for AD or IIS.

SPA can be downloaded from www.microsoft.com/downloads/details.aspx?FamilyID=61a41d78-e4aa-47b9-901b-cf85da075a73&DisplayLang=en.

Background on Windows performance counters is available at www.microsoft.com/resources/documentation/WindowsServ/2003/all/deployguide/en-us/counters1_cudp.asp.

Background on ETW for IIS is available at www.microsoft.com/resources/documentation/IIS/6/all/techref/en-us/iisRG_TRB_6.mspx.