Time drift in HP UX servers

[user1221]

Hi,

Our 4 HP-UX (version 11.31)servers are some minutes ahead of the real world time, 2 servers are in Oracle RAC Cluster, Node1 is NTP server for Node2, they are ahead with 11 minutes, the other server has their own time and NTP is not configured on it.

Two weeks back when I checked the times on all the servers say it was 11 minutes ahead and now the time difference has increased by 28 seconds on RAC nodes and 25 seconds on third server and 2 seconds on the fourth server. That means the RAC nodes are now 11.28 seconds ahead.

Why there is increased in time difference?

We have Windows 2008 server which is The DNS and NTP server in our organization.

Can we configure the HP-UX servers with Windows 2008 NTP server?
If yes then please share the procedure.

Thanks and Best Regards.

[Kenan Erdey]

hi,

ntp is there to keep the time same on every hosts. if especially the time on one host is increasing, there may be a problem with the mainboard etc.

i don't suggest ntp server on windows if it's in domain. we had a lot issue. some servers lost synranisation with time server,time differences between cluster nodes went away so cluster nodes rebooted itself etc.

at least we got the ntp server out of domain.

[Rita C Workman]

It is always best to take at least one or two of your internal servers and have them time sync to an outside time-source server to set your time to.
There are many Internet time clock servers. Find one closest to you in your timezone.

Then internally you can then set your other servers to sync to those one or two internal servers that maintain true time with the outside source.

Rgrds,
Rita

[Rita C Workman]

Couple things.

Yes you could set your HPUX clocks to sync to the Windows server. But, again, that may not be true time. Does the windows server use a true time source?

And, when you go to fix your time, remember to be sure to shut Oracle down as it's transactions are very time dependent. And turning time back on Oracle is far more damaging than moving it forward. So be sure to shutdown/let those minutes pass/ then set your time and when all is syncing good/ turn Oracle back on.

Rgrds,
Rita

[Hakki Aydin Ucar]

At least you can find in internet any ntp OR clock server, and can use them as ntp clock. But a professional solution you can chose a professional clock providers with atomic clock.

[Bill Hassell]

All computers drift -- the clock in the computer is designed to sync the circuits, not keep accurate time so drifting is absolutely normal. NTP is the correct protocol to use and will keep most servers within a fraction of a second. Windows uses SNTP which is not very accurate (in NTP terms).

http://en.wikipedia.org/wiki/Network_Time_Protocol

If you point your servers at the Windows NTP server, accuracy will not be very good but all your servers will drift right along with the Windows boxes. I would rather keep a stable environment for Unix servers. Check to see if you can reach the Internet with one of your servers:

ntpq -p us.pool.ntp.org

If you can see several entries, then you can point one of your servers to the pool servers, and the rest of your servers can point to the first one.

[Horia Chirculescu]

Hello,

Please read the docs:

http://docs.hp.com/en/B2355-90110/ch08.html?btnPrev=%AB%A0prev

You should runt ntp on all 4 nodes and those would sync to an external ntp server (or even your windows server if this would be the only one connected to the 'ouside' world).

Best regards
Horia.

[user1221]

Thanks you your replies.

Our management decided that the time on each and every system in the organization will be the same and hence they want us to configure the HP-UX servers with Win 2008 NTP server.

The Win2008 NTP server is getting time from Microsoft's NTP server, I think from "time.microsoft.com"

Does any specific port needed to be open in the firewall for communication between the different platforms for setting NTP?

Please share the procedure to configure NTP on HP-UX servers with Windows server as NTP server for all.

Thanks!

[Rita C Workman]

You need to first find a time where you can stop Oracle, cause remember it's running on a box that is ahead of time. You do not want to force backing up time with Oracle. It is time dependent.

Edit /etc/rc.config.d/netdaemons
export NTPDATE_SERVER='your ntp server'
export XNTPD=1

Edit /etc/ntp.conf
server
driftfile /etc/ntp.drift

Then do a:
touch /etc/ntp.drift

Then start ntp:
/sbin/init.d/xntpd start

To check it:
ntpq -p

Rita

[Dan Bolton]

We run a mixed environment, HP-UX, Linux, and MS Windows. We initially had Windows servers as out local master, but we found it too unstable.

Now we have Linux boxes as our local masters syncing with public NTP sources and all HP-UX servers and the Windows DCs referencing them. (The Domain Controllers then pass time to the remaining Windows servers and PCs.)

I believe there were some registry changes on the DCs to work correctly with NTP. I can dig them up if there is any interest in this method.

[Horia Chirculescu]

>Does any specific port needed to be open in the firewall for communication between the different platforms for setting NTP?

Usually, firewalls are placed between the local network (organization's) and the exterior world.

Anyway, NTP uses UDP on port 123. So the firewall should pass traffic originated/to this port.

More info at official web site:

http://www.ntp.org/

http://www.eecis.udel.edu/~mills/ntp/html/build.html

Best regards,
Horia.

[Dan Bolton]

Maybe Win Server 2008 uses true NTP, but our 2003 Server DCs used Windows_Time_Service by default (similar to, but _NOT_ NTP). If it does, you could just configure your HP servers as NTP clients pointed at the Win Servers, [shudder] but my experiance would cause concern about constancy.

The other option would be to make HP-UX your masters, syncing to the external servers of your choice, then configuring Windows boxes to sync to them with the attached NTP-client registry changes. The Windows boxes can still pass the correct time to PCs via Windows_Time_Service with no changes required on the clients.

Good Luck

p.s. My apologies for posting a Windows Registry hack in an HP-UX forum

[Jim Walls]

Many modern routers and some switches offer ntp as a service. Ask your network engineer to check. Usually one (or better, two) of the routers/switches can be set up to keep time with external time services and then act as local time sources for the whole internal network. Once this is set up each internal server should be configured to use the local time sources. It is best to offer at least two independent sources so that if one goes down the other can be used. The ntp daemon decides which is the most accurate time source to use.

[user1221]

Our management insist to stick with the Windows 2008 server as the NTP server for the whole organization, I have configured it on all the HP-UX servers.

Thank you all for your help!