Understanding %D in LogFormat for apache2 logs

A colleague recently asked me if %D, when used in your LogFormat for apache2 access logs includes the ‘download’ time of transmitting the response back to the client.

Following are observations from my apache2 access logs when using the %D format code. The first column is %D in the following log entries.

# 5 second pause on [...]

Establishing Concurrency from your Web Logs

I recently had a conversation with a colleague about how one might determine the concurrency for a given page or transaction at any point in time. The system under test was a typical web server and we had access to the web logs for analysis.

That is, we wanted to know how many virtual users were [...]