Overview

You found that NTP is not synchronized after a planned SMSC server reboot in your Cobalt environment. This resulted in SMS KOs for SMPP traffic.

You request a server check, inquire about the root cause, and a way to avoid this issue.

Solution

Root Cause

It is likely that the following message will be observed related to the NTP service in the logs in your environment.
By logs, we refer to the syslog (/var/log/messages) from the SMSC server and the files under /var/log/ntpstats/ folder after the time the SMSC server was rebooted. 

ntpd[924]: frequency error 3601 PPM exceeds tolerance 500 PPM

ntpd[924]: frequency error 3601 PPM exceeds tolerance 500 PPM

ntpd[924]: frequency error 1232 PPM exceeds tolerance 500 PPM

ntpd[924]: frequency error 4161 PPM exceeds tolerance 500 PPM

• The time computed by ntpd and the one reported by the systems internal clock exceeding 500 PPM would lead to the observed log messages. If the difference exceeds 500 parts-per-million (0.0005) over the synchronization interval then the log message appears.

• Several root causes are possible for example, incorrectly working timesources in the system.

Steps

You can adjust the time manually to solve the synchronization problem. This is the same approach recommended by Red Hat as indicated in this link.

Adjusting the time with ntpd -qg

• As a first approach to solve the issue, the ntpd service should be stopped and the time be adjusted manually with the -qg option.

• This will only fix situations where the offset between ntpd computed time and internal clock is big, but the internal clock is working reasonably accurate (so can be compensated by ntpd):

  # service ntpd stop

1. ntpd -qg
2. service ntpd start

* Information about the above options from man page :-

  -g
Normally, ntpd exits if the offset exceeds the sanity limit, which is 1000 s by default. If the sanity limit is set to zero, no sanity checking is performed and any offset is acceptable. This option overrides the limit and allows the time to be set to any value without restriction; however, this can happen only once. After that, ntpd will exit if the limit is exceeded.
-q
Exit the ntpd just after the first time the clock is set. This behavior mimics that of the ntpdate program, which is to be retired. The -g and -x options can be used with this option.

For a server check, please raise a support ticket with us. Our PS team will connect to the SMSC server, check the required details including NTP status and inform you.