ASP.NET

This resource contains monitors specific to the current status of the ASP.NET IIS application requests which contain all the websites for the current application. The icons of the listed performance counters in the Statistic Name column change colors to reflect the listed counter's current state. Clicking any performance counter in the Statistic Name column takes you to the Performance Counter Details page for that performance counter.

If the value of a listed performance counter crosses the Warning threshold, the chart for the listed counter displays a yellow background. If the value of a listed monitor crosses the Critical threshold, the chart for the listed counter displays a red background. Hovering over any time period within the chart displays detailed information about that time period in the tooltip. Hovering over a counter gives you detailed information about that performance counter.

Counter Expert Knowledge Warn-
ing
Criti-
cal

Request Execution Time

Description:
This displays the number of milliseconds that it took to execute the most recent request.

Information:
The execution time begins when the HttpContext for the request is created, and stops before the response is sent to IIS. Assuming that user code does not call HttpResponse.Flush, this implies that execution time stops before sending any bytes to IIS, or to the client. When the process model is enabled, the request execution time includes the time required to write the response to the client, and therefore depends upon the bandwidth of the client's connection. There is no threshold for this counter. The value of this counter should be stable. Experience helps you set a threshold for a particular site.

Note: A baseline is required.

Sustained Status: 3 out of 5 polls Sustained Status: 4 out of 4 polls

Request Wait Time

Description:
This displays the number of milliseconds that the most recent request was waiting in the queue.

Information:
This does not include any time spent waiting in application queues. The threshold for this counter is 1,000. The average request should spend 0 milliseconds waiting in the queue.

Possible problems:
If this indicator is greater than 1,000 ms, the performance of the IIS server is suffering.

> 300 > 900

Requests Queued

Description:
This displays the number of requests waiting to be processed.

Information:
The Aspnet_wp process queue is a named pipe through which the request is sent from one process to the other. The number of requests in this queue increases if there is a shortage of available I/O threads in the Aspnet_wp process. When the limit specified by <processModel requestQueueLimit=/> is exceeded, requests are rejected with a 503 error (Service Unavailable). Note that if a request is rejected for this reason, it will never reach managed code and error handlers will not be notified. Normally this only occurs when the server is under a very heavy load. Virtual directory queues maintain the availability of worker and I/O threads. The number of requests in these queues increases if the number of available worker threads or available I/O threads falls below the limit specified by <httpRuntime minFreeThreads=/>. When the limit specified by <httpRuntime appRequestQueueLimit=/> is exceeded, the request is rejected with a 503 error and the client is sent an HTTP exception with the message, Service Unavailable.

Possible problems:
When this value starts to increment linearly with increased client load, the web server computer has reached the limit of concurrent requests that it can process.

Remediation:
The default maximum value for this counter is 5,000. You can change this setting in the Machine.config file.

Note: A baseline is required.

> 2000 Sustained Status: 3 out of 5 polls

> 4000 Sustained Status: 3 out of 5 polls

Requests Rejected

Description:
This displays the number of requests rejected because the request queue was full.

Information:
Requests are rejected when one of the queue limits is exceeded. Back-end latency, such as that caused by a slow computer running SQL Server, is often preceded by a sudden increase in the number of pipeline instances and a decrease in % Processor Time and Requests/second. A server might be overwhelmed during times of heavy load due to processor or memory constraints that ultimately result in the rejection of requests.

Possible problems:
The value of this counter should be 0. Values greater than 0 should be investigated.

N/A > 0

Zooming

You can have the chart show a predetermined time period of data by clicking on any one of the three Zoom buttons in the head of the Zoom column. Alternatively, you can have the chart show a specific date range by dragging the mouse over an area of the chart. The time and date displayed at the top of the resource shows the amount of data currently loaded into the chart. This can be changed by clicking Edit from within the resource.

The Value from Last Poll column shows the most recent data available for the listed statistic.