mod_logio module provides the logging of input and output number of bytes received/sent per request. The numbers reflect the actual bytes as received on the network and take into account the headers and bodies of requests and responses. The counting is performed before SSL/TLS on input and after SSL/TLS on output, so the numbers will correctly reflect any changes made by encryption.

This module requires mod_log_config.

Format String

The module introduces two new logging directives. The characteristics of the request are logged by placing "%" directives into the format string, which are replaced in the log file by the values as follows:

Format Description
%I Bytes received, including request and headers. Cannot be zero
%O Bytes sent, including headers. Cannot be zero

Usually the custom log format with %I & %O directives looks like:


"%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\" %I %O"