NTPD service restart and time synch

Login or Register for Dates, Times and to Reply

 
Thread Tools Search this Thread
Operating Systems Linux Red Hat NTPD service restart and time synch
# 1  
NTPD service restart and time synch

I am using ntpd service to sync our RHEL 5.9 system to synch with GPS clock.
When I change the RHEL system time more than 7 seconds than the present system time (through "Datetime" command), ntpd service does not adjust the system time to the present GPS time.But if the time is with in 7 seconds, the system time is correctly adjusted after we change the system time manually by "datetime" command.
7 second is specified in our drift file. Once I restarts the ntpd service manually, the time is again adjusted with the present GPS time. I have read many article in google and my understanding from the articles are as follows.

The ntpd service adjusts the drift (drift is specified in drift file).It assumes that systeem clock should be always synched with the GPS clock (reliable time source) unless and until ntpd
malfunctions. Can any one tell how ntpd works in comparison with W32tm service in window system?
# 2  
Do you have "ntpdate peers" in /etc/ntp/step-tickers?
Is your system a virtual host (which one)?
Please give output of
Code:
ps -eo args | grep '[n]tpd'

# 3  
Q1Smilieo you have ntpdate peers in /etc/ntp/step-tickers?
Ans: Yes.The name of GPS Clock device is mentioned their.

Q2: Is your system a virtual host (which one)?
Ans: Do you mean to Say whether it is a virtual machine or not?
Is so then, we are having mix setup. The machine from where I am giving you the command output of Q3 is a Virtual Machine hosted in VM (VMWare Esxi 6.0.0)
and there are other machines (RHEL 5.9 basesd) whish are not VM are also having the same observations asked in the questions.

Q3: Please give output of:
Code:
ps -eo args | grep '[n]tpd'

Ans:
Code:
ntpd -u ntp:ntp -p /var/run/ntpd.pid


Last edited by Don Cragun; 02-28-2017 at 02:38 AM.. Reason: Add CODE and ICODE tags.
# 4  
If your problem is only with the virtual machines (VMware guests),
then you need to look into the VMware hosts. Do they have the correct time, are they running ntp?
Then, they might provide different modes for the guest's HW clock. A VMware expert might know more. But should not matter if the HW clock is correct.
# 5  
No.The same problem persist for the RHEL 5.9 machines that are non VM.
# 6  
If you have the NTP configuration correct, then I would use ntpdate timeserver to get the clock to jump to the correct time. Remember that this will set the system clock to CUT/UTC/GMT/ZULU and it is the timezone that changes the displayed date. You may be changing the date to what looks correct, but it is too far out for NTP to then follow the external source. NTP always follows the zero timezone.



Does this help?

Robin
# 7  
That's what it does with the servers in /etc/ntp/step-tickers
You do not need a driftfile.
If your driftfile makes problems, check if it has got the right permissions ntp:ntp
For example the pathname is /var/lib/ntp/ntp.drift
Code:
ls -ld /var/lib/ntp/ntp.drift /var/lib/ntp
drwxr-xr-x 2 ntp ntp  date  /var/lib/ntp
-rw-r--r-- 1 ntp ntp  date  /var/lib/ntp/ntp.drift

And initially this file should be empty, so the then started ntpd will write it after some hours according to its measurement.
A good debug command for the ntpd is
Code:
ntpq -p

or
Code:
ntpq -np

This User Gave Thanks to MadeInGermany For This Post:
Login or Register for Dates, Times and to Reply

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

Test Your Knowledge in Computers #982
Difficulty: Medium
NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD).
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Time synch monitoring

I'm using a debian variant. My system clock already auto synchronizes. I'd like to have some sort of alert or log entry if the time is ever off by more than a particular amount. My first choice is to have a new file created on the desktop each day that there is a slip greater than the specified... (4 Replies)
Discussion started by: jutnobs
4 Replies

2. Red Hat

Apache service not coming up after restart

When I update the server with new SSL certificates, and restart httpd, I get errors : # service httpd restart Stopping httpd: rm: cannot remove `/usr/local/apache2/bin/httpd/logs/httpd.pid': Not a directory Starting httpd: ... (0 Replies)
Discussion started by: anaigini45
0 Replies

3. Red Hat

Restart service xinit.d or init.d ?

Hello How do I restart init.d ?? (centos 6.5) Thanks (2 Replies)
Discussion started by: mnnn
2 Replies

4. Red Hat

Service restart and check if running

Hello, I'l like to create a script that restart a service (/etc/init.d/httpd restart) and also check if after restart the service is actually running. Sometimes it happen that at the first try the service fails to restart. Thanks (2 Replies)
Discussion started by: bazzola
2 Replies

5. SuSE

Service restart daily

Hi, Beside using crontab, what is other application we can set it? Normally I check using command crontab -l. Any other path I need to check? Please guide me. Thanks. (2 Replies)
Discussion started by: mzainal
2 Replies

6. Shell Programming and Scripting

how to synch 2 processes to start at the same time

Hey Excuse me if this question is repeated everywhere but I am still new with scripting and I couldn't apply what I found to my case :confused::confused: I am trying to run a rec process on a ssh client and at the same time play a file from my computer so i tried this #!/bin/bash echo... (3 Replies)
Discussion started by: Antaha
3 Replies

7. Shell Programming and Scripting

Need to Restart Service with Password

Hi All, Requirement : I need to check for some services in my environment and restart the service if its not running. I have written script to check the script if its running or not. While if its not running i need to restart it using ./start command. But it will ask for password prompt and i... (4 Replies)
Discussion started by: pradeepbaliga
4 Replies

8. HP-UX

Script to auto restart a service

Hi All, May i please know if it is possible to write a script to check the log messages and automatically restart a service if it is failed or it is stopped. Appreciate your suggestions. Thanks in advance. regards, Eajaz (2 Replies)
Discussion started by: ajazshariff
2 Replies

9. Shell Programming and Scripting

Restart a Service!!

Hello, I am trying to write a script which will monitor few processes(winbind) for cpu utilization, If the process consumes more than say 99% cpu for 3 minutes, I want to run a script to restart the service which forks the process. ---------- Post updated at 11:21 AM ---------- Previous update... (5 Replies)
Discussion started by: linuxaddict7
5 Replies

10. UNIX for Dummies Questions & Answers

Service Restart Netbackup

For vertitas netbackup 6.0 I have media server :Solaris Client server: Windows I want to restart the netbackup service on the media server . plz suggest ASAP. (1 Reply)
Discussion started by: saurabh84g
1 Replies

Featured Tech Videos