The issue appear after upgrading and old Apache2.2 to Apache2.4.
~# service apache2 restart * Restarting web server apache2 [fail] * The apache2 configtest failed. Output of config test was: AH00526: Syntax error on line 11 of /etc/apache2/sites-enabled/www-mycompany: Invalid command 'RewriteLog', perhaps misspelled or defined by a module not included in the server configuration Action 'configtest' failed. The Apache error log may have more information.
Earlier versions of mod_rewrite use RewriteLog and RewriteLogLevel directives. This functionality has been completely replaced by new per-module logging configuration like mentioned on apache docs
~# cat /etc/apache2/sites-enabled/www-mycompany | grep LogLevel LogLevel alert rewrite:trace3
To get just the mod_rewrite-specific log messages, pipe the log file through grep:
~# tail -f error_log|fgrep '[rewrite:'