IIS 7.0 - Application Pool Recycles - Log a event in Windows Event Log

ganeshanekar — Fri, 12 Dec 2008 13:18:00 GMT

This is my 1st blog post on IIS 7.0.

Application Logging

Apart from the standard IIS logs type, other items can be logged. Many of these options can be set in UI using the IIS Manager or by using Appcmd.exe - IIS command line administration Tool.

Application Pool - Process Recycling Logging

In IIS 7.0, events are logged to the Windows event log when an application pool recycles. You can control eight recycling application pool configuration settings with each option listed in Table below:

Recycling Options Under Generate Recycle Event Log Entry
Option	Description	Default Setting
Application Pool Configuration Changed	Event is logged when the application pool recycles due to a change in its configuration	No
ISAPI Report Unhealthy	Event is logged because an ISAPI extension has reported itself as unhealthy	No
Manual Recycle	Event is logged when the application pool has been manually recycled	No
Private Memory Limit Exceeded	Event is logged when the application pool recycles after exceeding its private memory limit	Yes
Regular Time Interval	Event is logged when the application pool recycles on its scheduled interval	Yes
Request Limit Exceeded	Event is logged when the application pool recycles after exceeding its request limit	No
Specific Time	Event is logged when the application pool recycles at a scheduled time	No
Virtual Memory Limit Exceeded	Event is logged when the application pool recycles after exceeding its virtual memory limits	Yes

In IIS Manage UI, you can find above options as below:

1. Open IIS Manager

2. Go application pools.

3. Highlight the application pool and select "Advanced Settings".

4. Under Recycling, Expand "Generate Recycle Event Log Entry"

Classic ASP Error Logging:

For Classic ASP (Active Server Pages) in IIS 7.0, you can configure options for logging ASP errors under the ASP section in the IIS Manager. You may use the following options to discover issues when migrating your Classic ASP applications to IIS 7.0.

Enable Log Error Requests - Controls whether the Web server writes ASP errors to the application event log
Log Errors To The NT Log - Specifies that ASP errors are recorded in the Windows event log

Note: These options are also available in IIS 6.0, but you have to use ADSUtil.vbs to enable them in the metabase. Now, in IIS 7.0, you can use the IIS Manager to enable these options or use command line appcmd.exe tool.

Logging ASP.NET Exceptions:

All ASP.NET 2.0 unhandled exceptions are always written to the Application Event log. Along with application pool recycle events or other errors in the event logs, this can be very helpful in troubleshooting application errors. It is always a good idea to debug Unhandled Exceptions in ASP.NET. See following blogs for more information:

Debugging Unhandled Exceptions in ASP.NET
Learning how to Debug ASP.NET App Issues (Memory Leaks, Crashes, Deadlocks, etc)

IIS 6.0 Events Reference
IIS logs events in the windows event viewer which helps to analyze performance and troubleshooting. Review "Event Reference" for more information.

Ganesh Anekar's Blog : Logging

IIS 7.0 - Application Pool Recycles - Log a event in Windows Event Log