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NTP POLLING ISSUE

RajuD
Frequent Advisor

NTP POLLING ISSUE

Dear All,

Can we use router as NTP server?

I have configured my ntp client as hpux box and server as router, the problem i am facing is ntp polling is not happening? please suggest.
“Education is our passport to the future, for tomorrow belongs to those who prepare for it today.”
8 REPLIES
Patrick Wallek
Honored Contributor

Re: NTP POLLING ISSUE

>>Can we use router as NTP server?

Yes, as long as the router is configured as an NTP server and is running the XNTPD daemon, or its equivalent.

>>the problem i am facing is ntp polling is not happening?

What does 'ntpq -p' show?

What about 'ntpq -p '?
Patrick Wallek
Honored Contributor

Re: NTP POLLING ISSUE

Also, are you sure XNTPD is running on your HPUX server? 'ps -ef |grep ntp'
RajuD
Frequent Advisor

Re: NTP POLLING ISSUE

Hi Patrick,

Thanks for the immediate responce...

IN CLIENT SIDE:
xntp daemon is running and i have attached the output of ntpq -p and daemon status.



The problem i am facing here is in step 4

Step 1
I have a configured the ntp client in hpux box.

Step 2
I have change the time 30 min forward in client pc. (ex: if the current time is 9.30am i have changed to 10.00am)

Step 3
i have started the xntpd service #/sbin/xntpd start. after starting the service when i checked the time it shows normal. (9.31am)

Step 4
After doing all this step
Once again i have changed the time 3 min forward client pc ......i have waited for 5 min to check the status............the polling is not happening and there is diff of 3 min between client and server......please suggest.
“Education is our passport to the future, for tomorrow belongs to those who prepare for it today.”
RajuD
Frequent Advisor

Re: NTP POLLING ISSUE

Dear All,

Polling is happening.........but takes 15min.

Question

I need to configure the ntp client in database server. please suggest do i need to bringdown the application and database in ntp client to sync. with ntp server which is having a time difference of 6min backward and forward. kindly suggest.
“Education is our passport to the future, for tomorrow belongs to those who prepare for it today.”
Bill Hassell
Honored Contributor

Re: NTP POLLING ISSUE

The ntpq -p information shows that the NTP server is working and xntpd is working on your HP-UX system.

> I have change the time 30 min forward in client pc.

What does this have to do with HP-UX or your NTP server? Are you pointing your PC to the HP-UX box as an NTP server?

Note that NTP can handle about a 10 minute difference in time. It will take HOURS to move the time back in sync if the difference is 10 minutes. Beyond about 10 minutes, NTP gives up because the difference will take more than a day to resync.

On the HP-UX side, the xntpd daemon will poll every 64 seconds (seen in the ntpq -p output). Once the time is accurate and the network is stable, the poll time will double to 64, then 128, etc. Fior a stable server and client, the longest poll time will be once every 1024 seconds (17 minutes).

> I need to configure the ntp client in database server.

Is this the HP-UX client from above, another HP-UX box or a PC?

> with ntp server which is having a time difference of 6min backward and forward

I have no idea what this means. Your NTP server maintains your reference time -- only clients might be different. 6 minutes will take a couple of hours to sync properly. If you run the ntpdate command or change the date, then yes, you must stop your application and database, make the change, then verify that ntpq -p shows normal communication and sync. After that, you can start your database and application.


Bill Hassell, sysadmin
mvpel
Trusted Contributor

Re: NTP POLLING ISSUE

If you run "ntpq -c peers" on the client, and there is a non-zero number in the delay and offset columns, then your NTP client is getting the information it needs from the NTP server.

The best way to test whether you're getting a usable chime from another system is to shut down xntpd and run "ntpdate" against the server hostname or IP address. You need to shut down xntpd because otherwise ntpdate can't grab port 123.

If ntpdate says "step time server offset " then you know that the client is capable of getting a valid chime back, and xntpd should work too.
BUPA IS
Respected Contributor

Re: NTP POLLING ISSUE

Hello,
@mvpel

> You need to shut down xntpd because otherwise ntpdate can't grab port 123.

ntpdate -q can be run against any time server even if ntpd is running. Exclusive use is only required if you want to update the clock .

ntpdate run on its own from root assumes you know what you are doing and it sets the clock. It should be used with -q first to check the status of the time servers' ability to give you the time and the size and direction of the change to your running client system this way you avoid unexepected time steps.
Most database engines do not like time being stepped backwards by large amounts.

Raju your ntp -q is fine execpt that it has only had one sucessful contact with the time server , you need to wait a few minutes and run it again.

Mike
Help is out there always!!!!!
RajuD
Frequent Advisor

Re: NTP POLLING ISSUE

thanks for your valuable time.
“Education is our passport to the future, for tomorrow belongs to those who prepare for it today.”