The LMS 3.0 system folder show >2G for syslog.log (the recommended size is 1G) and >12M (the recommdned size is 1M) for EDS-GCF.log. I am running out the system space so I need to move the syslog.log to a differenent directory. If possible, I will like to rotate to another file when it reaches certain size. I tried the logrot.pl -v without success.

As I said, syslogConf.pl will help you to relocate the syslog.log to a different directory. As for log rotation, you will first need to configure logrot using logrot.pl -c. Once you have added the log files to be rotated, then running logrot.pl without any arguments will rotate the log files provided their size matches the configured properties.

I was able to change the syslog.log to another driver using syslogconf.pl. I logon the LMS 3.0 after reboot the system. The log space usage and critical message window showed "loading". I also got error by trying to change the syslog.log back to $NMSROOT/log/ using the syslogconf.pl. It appears the NMSROOT variables is not defined in the system anymore.

NMSROOT is never actually defined on the system. It is defined at runtime by the various components from LMS. What was the exact error you got trying to change the log location back? Please also post the CSPortal.log.