Apache > HTTP Server > Documentation > Version 2.4 > Modules

Apache Module mod_logio

Available Languages:  en  |  fr  |  ja  |  ko  |  tr 

Description:Logging of input and output bytes per request
Module Identifier:logio_module
Source File:mod_logio.c


This 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, which then takes into account the headers and bodies of requests and responses. The counting is done 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.

When KeepAlive connections are used with SSL, the overhead of the SSL handshake is reflected in the byte count of the first request on the connection. When per-directory SSL renegotiation occurs, the bytes are associated with the request that triggered the renegotiation.


This module provides no directives.


See also


Custom Log Formats

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

Format String Description
%I Bytes received, including request and headers, cannot be zero.
%O Bytes sent, including headers, cannot be zero.
%S Bytes transferred (received and sent), including request and headers, cannot be zero. This is the combination of %I and %O.
Available in Apache 2.4.7 and later

Usually, the functionality is used like this:

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

Available Languages:  en  |  fr  |  ja  |  ko  |  tr 



This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.