Apache Reference: mod_cgi, ScriptLogLength
Maximum Size of CGI Error Log File
Syntax: ScriptLogLength A
Example: ScriptLogLength 512000
Since: Apache 1.2
This directive limits the size of the CGI script log file. Because this file holds a great deal of information for each CGI error (all request headers, all script output), it can grow quite large. To prevent problems caused by unbounded growth, you can use this directive to set a maximum file size (in bytes) for the CGI log file. If the file exceeds this size, no more information will be written to it.