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Time change forward 18 minutes

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Steve Ray Badgett
Occasional Contributor

Time change forward 18 minutes

We have a HP-UX 11.11 with Oracle 10.2.0.4.0 and I want to move the server system time 18 minutes forward. Do I need to shut down Oracle to move the time forward?

As root I will use
date -a +1080.100
with this be OK?
7 REPLIES
James R. Ferguson
Acclaimed Contributor
Solution

Re: Time change forward 18 minutes

Hi Steve:

Setting the time forward is usually OK.

However, slewing the clock to move 18-minutes is going to take some time (no pun intended). You might just step forward in one jump.

This aside, I hope that you are adjusting your clock in order for NTP to synchronize your server to an external time source.

Regards!

...JRF...
Steve Ray Badgett
Occasional Contributor

Re: Time change forward 18 minutes

NTP will be the all time fix on this and will be discussed.

A small test was showing this should take 15 minutes to adjust it forward 18 minutes. Knowing this it might be better to just do the jump.

Thank you for the help.
Bill Hassell
Honored Contributor

Re: Time change forward 18 minutes

NTP can't handle more than about 10-12 minutes of slewing. The date command might be able to but be aware that it could take more than one day and the new day may cause a problem. You can test this (if you have several days to experiment) but I would not jump the change even though it is forward with Oracle running. There are small windows during updates where timestamps should be similar and you may end up with some corrupt records because they should be within a few seconds of each other.

Either shutdown the apps plus Oracle and make the change or reboot and set the time before Oracle starts. If you are using NTP, the reboot will jump the time before any apps start.


Bill Hassell, sysadmin
Steve Ray Badgett
Occasional Contributor

Re: Time change forward 18 minutes

We are not using NTP, it is going to be looked at if feasable.

I have tested date -a +420 and this took a few minutes local. Would date -a +420.100 take longer?
Bill Hassell
Honored Contributor

Re: Time change forward 18 minutes

> I have tested date -a +420 and this took a few minutes local. Would date -a +420.100 take longer?

The date command apparently slews the clock a *LOT* faster than ntp. The man page is silent about how fast this change is made as well as any side effects.


Bill Hassell, sysadmin
Steve Ray Badgett
Occasional Contributor

Re: Time change forward 18 minutes

I did the date -a +1080

this took nearly one hour to see the 18 minute avancement

I watched with . . .

while true
do
date
sleep 5
done

This reported ever 5 seconds with a 2 second advance each time but once in a while it would be a 2 second. This went without issues and was pleased withthe results.

Thanks for all your help and direction
Khairul_1
Frequent Advisor

Re: Time change forward 18 minutes

Hi Steve Ray,

It is best to down Oracle DB before change any system time forward or backward.Because it will effect on your ONLINE Database.

You can use date 032316552010.

#date MonthDateHourMinutesYear

You can forward 18 minutes from your present time. It will effect immediately.

Thanks
Khairul