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System Monitoring for HTTP

September 26, 2017

I’ve written about system monitors in Navigator for i two times before; first when system monitors were added to Navigator in IBM i 7.2, and then later, when system monitors were enhanced with Visualize Monitor Data in the 7.3 release (which has also been taken back to IBM i 7.2).

In this blog, I’d like to review the HTTP metrics that were added to system monitors in Navigator for i in the 7.3 release. This support has not been taken back to 7.2.

Collection Services has collected HTTP metrics for many years. In fact, you’ve probably been collecting HTTP metrics and didn’t even know it. When you use Collection Services’ default collection profile, Standard plus Protocol (*STANDARDP on the CFGPFRCOL command), HTTP server metrics are automatically collected. While this data is collected, it isn’t graphically visualized by any of the IBM interfaces; neither the Performance Data Investigator nor iDoctor have graphs to display the HTTP metrics.

However, now in the 7.3 release, you can set up a system monitor on HTTP metrics.  System monitor metrics are also collected by Collection Services. Note that these HTTP monitor metrics are for all HTTP servers in the partition.

You can monitor HTTP metrics to gauge the overall health of your web applications. When you know what your typical high rates are, you can set thresholds on the monitors to be automatically notified if unusually high rates are occurring so you can identify and respond to the situation in a timely manner. If you see unexpectedly high values (which of course depends upon your environment), you can use the IBM Web Administration (Internet Configurations task from Navigator) to review real time server statistics.

You can find additional information on IBM HTTP Server Performance and Managing HTTP Server performance in the IBM Knowledge Center.


You can find information about all of the monitor metrics in the IBM i Knowledge Center. For your convenience, I’ve listed the HTTP monitor metrics below.

HTTP Requests Received Rate
The number of requests received per second for all HTTP servers.  

HTTP Requests Received (Maximum)
The largest number of HTTP requests received by a single server.  

HTTP Responses Sent Rate
The number of responses sent per second for all HTTP servers.  

HTTP Responses Sent (Maximum)
The largest number of HTTP responses sent by a single server.

HTTP Non-Cached Requests Processed (Average and Maximum)
The number of non-cached requests processed for HTTP servers.

HTTP Error Responses Sent (Average and Maximum)
The number of error responses sent for HTTP servers.

HTTP Non-Cached Requests Processing Time (Total and Highest Average)
The processing time for non-cached requests for HTTP servers.

HTTP Cached Requests Processing Time (Total and Highest Average)
The processing time for cached requests for HTTP servers.

If you are wondering what each of these metrics mean, you can find their definitions in the real time server statistics help (the question mark in the screen capture).  



For your convenience, I have included the definitions below.

Requests
Displays the number of requests to the enabled function or associated server identified at the top of the column.

Responses
Displays the number of responses sent by the enabled function or associated server identified at the top of the column.

Error responses
Displays the number of error responses sent by the enabled function or associated server identified at the top of the column. An error response example is the 404 "Page Not Found" response.

Non-cache responses
Displays the number of non-cached responses sent by the enabled function or associated server identified at the top of the column.

Cache responses
Displays the number of local memory cached responses sent by the enabled function or associated server identified at the top of the column.

Bytes received
Displays the number of bytes received by the enabled function or associated server identified at the top of the column.

Bytes sent
Displays the number of bytes sent by the enabled function or associated server identified at the top of the column.

Non-cache Processing (seconds)
Displays the number of seconds of non-cached processing activity completed by the enabled function or associated server identified at the top of the column.

Cache Processing (seconds)
Displays the number of seconds of cached processing activity completed by the enabled function or associated server identified at the top of the column.

Posted September 26, 2017 | Permalink

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