topic Re: System Time wrong... in Operating System - Linux

System Time wrong...

John Collier — Thu, 09 Mar 2006 17:12:27 GMT

Seems as if two of my FC4 boxes are not updating via NTP as I would expect them to while the other one is working like a champ.

I have checked to verify that the NTP service is running on all of them and it is.

ps -ef | grep ntp | grep -v grep
ntp 2879 1 0 Feb10 ? 00:00:13 ntpd -u ntp:ntp -p /var/run/ntpd.pid

They all give the same info for the above command (with the PID being different, of course), yet they all seem to be displaying different times.

What am I overlooking?

Re: System Time wrong...

Ivan Ferreira — Thu, 09 Mar 2006 17:22:18 GMT

The command to test if you are synchronizing the time correctly is:

ntpq -pn

You should see a list like this:

remote refid st t when poll reach delay offset jitter
==============================================================================
*10.10.10.10 146.164.48.5 2 u 56 64 377 -0.023 390.197 148.586

The * indicates that that is the server for this node. If you don't see the "*", stop the ntpservice and run:

ntpdate -b ntp.server

And start the service. Also ensure that no firewall is blocking the connection to the ntp server.

Re: System Time wrong...

John Collier — Thu, 09 Mar 2006 17:36:04 GMT

Ivan,

All three of them (the one working and the two not) are on the same network going through the same router and using outside, public time servers.

Each of them have several entries when I run the ntpq -pn command:

From the working system:

+80.127.4.179 .PG0A. 1 u 441 1024 377 145.249 -0.761 1.130
+72.3.133.147 129.6.15.29 2 u 383 1024 377 27.063 -0.238 1.689
-64.172.230.138 164.67.62.194 2 u 72 1024 377 86.241 11.109 12.325
66.187.224.4 .INIT. 16 u - 1024 0 0.000 0.000 4000.00
*66.187.224.4 .CDMA. 1 u 403 1024 377 63.016 0.233 1.113

From the first non-working system:

+192.36.143.151 .PPS. 1 u 758 1024 377 186.287 -13.942 7.197
-24.34.79.42 132.163.4.103 2 u 737 1024 377 88.984 1.932 1.774
-64.112.189.11 128.10.252.6 2 u 589 1024 377 81.008 2.090 6.420
+66.187.233.4 .CDMA. 1 u 680 1024 377 52.510 -6.552 4.299
*66.187.224.4 .CDMA. 1 u 974 1024 375 63.270 -3.971 3.298

And from the last non-working system:

-64.34.193.47 195.137.27.138 3 u 879 1024 377 75.975 -11.893 7.095
-64.81.84.140 216.52.237.152 3 u 825 1024 377 78.760 -51.992 5.749
+216.237.126.10 132.239.1.6 2 u 831 1024 377 66.145 0.571 1.970
+66.187.233.4 .CDMA. 1 u 849 1024 377 71.435 -8.258 14.280
*66.187.224.4 .CDMA. 1 u 15 1024 377 64.283 0.236 1.794

As you see, all of them have an * next to the same entry, yet they all display different times. Do I have a "ghost in the machine" thing going on here?

Re: System Time wrong...

Ivan Ferreira — Thu, 09 Mar 2006 17:51:21 GMT

Check your timezone configuration. Verify the file /etc/sysconfig/clock. If you do some changes, reboot your computer.

How bad is the time displayed?

What is the ouput of:

date +%z
date +%Z

Re: System Time wrong...

John Collier — Thu, 09 Mar 2006 18:09:30 GMT

Looking at all the /etc/sysconfig/clock files I see that they are all identical:

ZONE="America/North_Dakota/Center"
UTC=false
ARC=false

The one that is correct and one of the others (that is not) both have the same output from the two commands:

date +%z
-0600

date +%Z
CST

The last one displays something slightly different:

date +%z
+0000

date +%Z
UTC

This tells me that the last one is in the wrong time zone (UTC vs CST). I forget where to change that since it is usually a set-and-forget type thing, but it does not explain why the two that are set the same still display differnt times.

Guess the first thing to do is to find where to change the one to the UTC and then move on from there...

Re: System Time wrong...

Ivan Ferreira — Fri, 10 Mar 2006 07:10:42 GMT

The time is displayed wrong because there is something bad with your time zone configuration. Your GMT-UTC offset is different, and that's why you get the wrong date. Verify if you have set the TZ environment variable.

echo $TZ

Re: System Time wrong...

Ivan Ferreira — Fri, 10 Mar 2006 07:44:12 GMT

You can also try replacing your current /etc/localtime file with a fresh one:

cp /usr/share/zoneinfo/America/North_Dakota/Center /etc/localtime

This is executed at boot time according to the configuration of /etc/sysconfig/clock

Re: System Time wrong...

John Collier — Fri, 10 Mar 2006 12:24:32 GMT

Ivan,

Thanks for the input. I am at work now, but I will see what I can do with the systems when I get home.

Silly question:

In order to make any of these suggestions work, you have to make these changes as root, right?

Re: System Time wrong...

Ivan Ferreira — Fri, 10 Mar 2006 12:48:06 GMT

The replacement of the /etc/localtime file you must do as root, but the TZ environment variable is per user configurable. If you want to configure it for all users, add it to /etc/profile:

export TZ="zonename"

Re: System Time wrong...

John Collier — Fri, 10 Mar 2006 19:29:14 GMT

Ivan,

It would seem as if I do not have the TZ environment variable set. When I run the

echo $TZ

I get no response at all. Just another command prompt.

I did take your advise and copied over a fresh localtime file using the command you suggested. What got my attention is that it did not complain about overwriting a file when I ran the command as I would have expected. Now i wish I would have checked the existence of the file prior to running the command. Oh well.

Now that it is copied over, I have to wait until she is no longer using it to reboot.

Strange thing. Seems as if the $TZ is not set on any of the boxes, but yet one of them is fine. I guess I still have a great deal of learning to do in regards to setting system time in Linux.

I will update this thread when there is something more to report.

Thanks for all the help so far!

Re: System Time wrong...

Ivan Ferreira — Sat, 11 Mar 2006 22:31:39 GMT

You don't have to reboot the system if you did the cp command. You only need to reboot if you change the /etc/sysconfig/clock file and do not run the cp command.

The TZ variable could not be defined, by default, it's not defined. I just told you to check that just in case.

Re: System Time wrong...

John Collier — Thu, 08 Jun 2006 14:32:05 GMT

Time on all boxes now correct. Thanks for the help!