5 Useful Performance Counters to Monitor for IIS

Internet Information Services (IIS) brings your websites live with a robust infrastructure at fast speeds. Even the default configuration is optimized for speed, you may notice slowness loading your websites due to possible reasons such as the inefficient application code. Here are 5 performance counters I would recommend checking if you want to monitor the resource usage in your IIS server:

  • Processor (All instances – % Processor Time): CPU consumption broken down by processes
  • Memory (Available Mbytes): Available memory in OS
  • HTTP Service Request Queues (CurrentQueueSize): The request count that is pending in the IIS queue
  • .NET CLR Exceptions (# of Exceptions Thrown/sec): The count of System.NullReferenceException thrown by the applications
  • APP_POOL_WAS (For all listed Application Pools):
    • Current Application Pool State: allows you to see the state of application pools
    • Current Application Pool Uptime: Allows you to see if the web application has been restarted or not
IIS performance counters in Performance Monitor
Recommended counters to monitor for IIS performance

In order to monitor these counters, follow the steps below:

  1. Go to Start. Search for “Performance Monitor
  2. Click on the green plus sign (+)
  3. Select a category (Processor, Memory etc.)
  4. Select a sub-category (% Processor Time, Available Mbytes etc.)
  5. Select an object (_Total, <All instances> etc.)
  6. Click “Add
  7. Click “OK

With these instructions, you can monitor the real-time statistics of your server. If you want to save these statistics:

  1. Right click on “Performance Monitor” under “Monitoring Tools” on the left side
  2. Select “New > Data Collector Set
  3. Give a name and click “Next
  4. Select a path to save the data and click “Next
  5. Select “Start this data collector set now” and click “Finish
  6. You will see an arrow icon on the collector set you created. It means it’s recording the logs. Once you have recorded for a desired time, right click on the collector set and select “Stop
  7. You can go to the path you specified in Step 4 or you can click “Latest report” button (Green notebook icon) to see the report
Report of IIS performance counters
Saved report of a data collector set

If you are not happy with your server’s resource usage and you want to fine-tune IIS performance, check my detailed post: 9 Easy and Practical Recommendations to Improve IIS Performance

For more performance counters related to IIS and ASP.NET, check these posts out:

9 Easy and Practical Recommendations to Improve IIS Performance

IIS hosts millions of websites around the world. Thanks to IIS Manager, it is easy to create and manage websites. Websites use default functional and performance settings which are efficient most of the time. However, you may want to fine-tune IIS performance for specific applications and cases.

Fine-tuning IIS Performance

In this post, I will explain 8 recommendations that potentially improves IIS performance. Most of the recommendations are compatible with IIS 7.0 and newer versions with a few exceptions. I will mention the exceptions in their respective section.

Recommendation areas:

  1. Output Caching
  2. Application Initialization
  3. Default Document
  4. HTTP keep-alive
  5. Cache-control Header
  6. Idle Time-out Action
  7. Dynamic Compression
  8. and 9. Other options (Queue Length, Enable 32-bit Applications)
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Solved: 503 Service Unavailable error related to Windows Admin Center

Windows Admin Center is a web application that makes it easier to manage multiple servers via multiple Microsoft tools such System Center, RSAT, Intune, and PowerShell. If you install Windows Admin Center in an IIS server, you may come across “503 Service Unavailable” error.

Note: This post explains 503 error related to Windows Admin Center only. If the root cause is not this product, check this post out: HTTP 503 Service Unavailable (Application pool has been disabled)

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