If you receive the following error,
Invalid command ‘BytesLog’, perhaps mis-spelled or defined by a module not included in the server configuration
while restarting apache in cPanel servers , do the following steps.
$ cd /usr/local/cpanel/apache
$ /usr/local/apache/bin/apxs -iac mod_log_bytes.c
$ /etc/rc.d/init.d/httpd restart
$ /usr/local/apache/bin/apxs -iac mod_log_bytes.c
$ /etc/rc.d/init.d/httpd restart
It will install the missing module and restart apache.