System time problem.

[Dong-Hwan Cha_1]

Hi All,

Sometimes, our system time has changed.
So, it is very difficult to sync with another system.
I'don't know the reason why the system time was changed.
How can I fix this problem?
(Our system's OS is HP 11.00.00)

Thanks & Regards.
Have a nice day!

[Mark Grant]

The best way is to start using "ntp".

ntp synchronizes time across different machines. It is described here.

http://networking.ringofsaturn.com/Protocols/ntp.php

[Dong-Hwan Cha_1]

Isn't there another way except ntp?
I want to fix this problem without using ntp.

[Mark Grant]

If port 13 is set up on your systems, you can always telnet to port 13 and adjust the time from that using a script.

[V. Nyga]

Hi,

is time changing after system has been switched off?

Volkmar

[Dong-Hwan Cha_1]

In Addition, if the system time has been changed after power off and on.
Is there any problem with hardware itself?

[Dong-Hwan Cha_1]

Hi Volkmar,

Maybe the problem was occurred after power off the system.
Do you know the reason why?

[SAHA]

System time change can occur due to faulty clock crystal (hardware). How much time it is changing .....
It is very difficult to give perfect clock without NTP.
Even you are not interested in syncing time from satellite source (need more money),
still you can atleast sync among your servers ....easy configuration.

Thanks,

[V. Nyga · Accepted solution]

Hi again,

when the problem was occurred after power off the system, then you have to replace the battery at the mainboard.

Please check your 'Owner's guide' or search for example here:
http://www.openpa.net/systems/
for your system and then for the Owner's guide.

Hope this helps
Volkmar

[Victor Fridyev]

Hi,

NTP is the best method for time synchrinization, it doesn't disturb any application.
If you don't want to use NTP (why ?), you can use the command
/usr/sbin/ntpdate -b SOMEHOST
which should be run by cron on all machines which need time synchronization.
This is not the best solution, because the command really set date on computer.

HTH

[Geoff Wild]

ntp is the best way to keep your clocks in sync....

If you don't want to use ntp, you could always script something to sync to the other system, something like:


date `remsh OTHERSYSTEM date "+%m%d%H%M"`

Rgds...Geoff

[Bill Hassell]

The date command can be run by any user and the time changed by any root user. That's why it is a dangerous command and should be wrappered to prevent accidental changes. The time will not change while the system is running unless someone types the date command (with a new value) or runs some special program that calls stime(2). The time is changing at reboot because the hardware clock is not being maintained (battery problem).

NTP is the recommended method for production servers since it is extremely accurate and has virtually no overhead. All other techniques will step-change the time which can be a bad thing for databases.

[Thomas Bianco]

why wouldn't you want to use NTP? it's stable, passive, unobtrusive, simple...

you might consider ntpdate, it's a runonce version of ntp, but the deamon version is MUCH better as it can speed/slow the clock closer to true seconds.

even if you don't connect to a time source, it's a good idea to set up all your servers as PEER servers the connect your clients to one of the PEER servers. this will atleast get a single definition of time across your network (even if it's not connecting with the true time)

[Dong-Hwan Cha_1]

Thanks for reply with my question.

Today I found the reason.
This problem was occurred by did not patch.
The problem was solved by patch.

Thanks.