ntpd frequency error -648 PPM exceeds tolerance 500 PPM

ntpd[xxxxx]: frequency error -648 PPM exceeds tolerance 500 PPM

Some time you will get errors as given below in /var/log/messages file, while troubleshooting about NTP issues. 

 9 Feb 11:39:49 ntpd[19959]: frequency error -653 PPM exceeds tolerance 500 PPM
 9 Feb 11:41:58 ntpd[19959]: frequency error -651 PPM exceeds tolerance 500 PPM
 9 Feb 11:46:12 ntpd[19959]: frequency error -650 PPM exceeds tolerance 500 PPM
 9 Feb 11:49:49 ntpd[19959]: frequency error -650 PPM exceeds tolerance 500 PPM
 9 Feb 11:53:44 ntpd[19959]: frequency error -649 PPM exceeds tolerance 500 PPM
 9 Feb 11:54:48 ntpd[19959]: frequency error -648 PPM exceeds tolerance 500 PPM

This issue basically refers to following reasons.

1. You have a problematic source.

2. NTP offset between ntpd computed time and internal clock is big.

Workaround:

the ntpd service should be stopped and the time be adjusted manually with the -qg option :

# service ntpd stop -- Stop the NTPD first

# ntpd -qg -- NTPD exits if offset exceeds sanity limit.

# service ntpd start -- Start the NTP

Permanent Solution:

Fix the NTP server