How to use the Debug Diagnostics tool to troubleshoot an IIS process that stops unexpectedly

When an IIS process that hosts a Web application stops unexpectedly, the system unloads the process, and all running requests are lost. To troubleshoot this scenario, you can use the Debug Diagnostic tool.

Use the Debug Diagnostics tool

You can use the Debug Diagnostic tool to generate and to analyze memory crash dumps. You want to capture a memory dump (.dmp) file before the process ends. To do this, follow these steps:

1. Download and then install the Debug Diagnostics 1.2 tool. To do this, visit the following Microsoft Web site:
   
   http://www.microsoft.com/download/en/details.aspx?id=26798
   
   
2. After you install the Debug Diagnostics tool, enable the Leave running when idle option for IIS 5.0 and IIS 5.1. To do this, follow these steps:
   1. Open the Component Services Microsoft Management Console (MMC) snap-in.
   2. Expand Component Services, expand Computers, expand My Computer, and then expand COM+ Applications
   3. Right-click any custom packages, Web sites, or Web directories, and then click Properties.
   4. Click the Advanced tab, click to select the Leave running when idle check box, and then click OK.
3. Disable the Enable debug exception catching option for IIS 5.0 and IIS 5.1. To do this, follow these steps:
   1. Open the IIS MMC snap-in.
   2. Right-click Web Sites, and then click Properties.
   3. Click the Home Directory tab, and then click Configuration.
   4. Click the Process Options tab, click to clear the Enable debug exception catching check box, and then click OK.
   5. Click OK to close the Web Sites Properties dialog box.
4. Disable Health Monitoring for IIS 6.0 and above. To do this, follow these steps: 
   1. Open the IIS MMC snap-in.
   2. Expand Application Pools.
   3. Right-click Application Pools, and then click Properties.
   4. Click the Recycling tab, and then click to clear all the Recycle worker process check boxes.
   5. Click the Performance tab, and then click to clear the Shutdown worker processes after being idle for (time in minutes) check box.
   6. Click the Health tab, click to clear the Enable rapid-fail protection and Enable pinging check boxes, and then click OK.
5. Restart IIS. To do this, click Start, click Run, type iisreset, and then click OK.

Create a crash rule in IIS 5.0 and in IIS 5.1

To create a crash rule in IIS 5.0 and in IIS 5.1, follow these steps:

1. Click Start, point to Programs, point to  Debug Diagnostics Tool, and then click Debug Diagnostics Tools 1.2.
2. Click Crash, and then click Next.
3. Select the desired Target Type, and then click Next.
4. Click Breakpoints, and then click Add Breakpoint.
5. Click ComSvcs!ComSvcsExceptionFilter.
6. In the Action Type list, click Full Userdump, and then click OK.
7. Click Save & Close, and then click Next.
8. In the Select Dump Location And Rule Name (Optional) dialog box, click Next.
9. Click to select the Activate the rule now check box, and then click Finish.

Create a crash rule in IIS 6.0 and above

To create a crash rule in IIS 6.0 and above, follow these steps:

1. Click Start, point to Programs, point to Debug Diagnostics Tool, and then click Debug Diagnostics Tools 1.2.
2. Click Crash, and then click Next.
3. Select the desired Target Type, and then click Next.
4. In the Advanced Configuration (Optional) dialog box, click Next.
5. In the Select Dump Location And Rule Name (Optional) dialog box, click Next.
6. Click to select the Activate the rule now check box, and then click Finish.

Manually obtain crash memory dump data

You can analyze crash memory dumps by manually obtaining the desired data. To do this, follow these steps:

1. Attach a debugger. To do this, follow these steps:
   1. Click Start, point to Programs, point to Debug Diagnostics Tool, and then click Debug Diagnostics Tools 1.2.
   2. Click the Processes tab.
   3. Right-click the process that you want to debug, and then click Attach Debugger.
2. In the Debug Diagnostics Tool window, notice that the Status for the new rule is Active. Additionally, the Userdump Count increases every time that a memory dump file is created.
3. Analyze the memory dump file by clicking the Advanced Analysis tab and then clicking Add Data Files.
4. When the .dmp file is added, click Crash/Hang Analyzers in the Available Analysis Scripts list, and then click Start Analysis.
5. When the analysis is finished, a .mht report is created in the C:\Program Files\DebugDiag\Reports folder and is displayed in Microsoft Internet Explorer together with the results and recommendations. 
6. If you use custom DLLs, you can add the Symbol Search Path For Analysis and the Symbol Search Path for Debugging settings to custom PDB files. To do this, follow these steps:
   1. On the Tools menu, click Options And Settings.
   2. Configure the Symbol Search Path For Analysis or Symbol Search Path for Debugging settings, and then click OK.