NTP - Advice on safe implementation

[Tim Krego_1]

I would like to configure NTP on our K460. I have set it up before, but this machine is running Oracle 8i and I know problems can happen when you make a drastic time change on a machine running a database.

It looks to me like I can set up NTP and have it make small incremental changes to the time over a several day timeframe.

Are there any precautions I need to take so I don't cause myself any problems?

Thanks

[A. Clay Stephenson]

Hi Tim:
I've run NTP on Oracle servers for many moons and it solves many, many more problems than it creates. The whole concept behind NTP is to introduce gradual time changes (essentially the clock speeds up or slows down rather than moving the hands) to the clients. I usally sync one server to the U. S. Naval Observatory
(navobs1.wustl.edu) and then sync all the other boxes to that box. If you are super picky
you can get a GPS timesoure.

If you are interested in the details, man adjtime(2) to see one of the key components.
NTP clients make use of this system call.

[James R. Ferguson · Accepted solution]

Hi Tim:

Stepping time forward is much less of a problem (if any, to a database) than moving it backwards.

Firstly, your local server time will not be sychronized with the external source if it differs by more than 1000 seconds, and the 'xntpd' daemon will eventually die.

Secondly, with 11.x, you can use the 'date' command to slew time gently:

# date [-a [-]sss[.fff]]

A very simple guide to setting up Network Time Protocol (NTP) is found in the "Installing and Administering Internet Services" manual:

http://docs.hp.com/hpux/onlinedocs/B2355-90685/B2355-90685.html

For a good list of available time sources, see:

http://www.eecis.udel.edu/~mills/ntp/clock1.htm
If you wish to merely synchronize locally take a look at Knowledge Base document #A5864817. You can use one of your servers as a "master" clock for the remaining ones without going outside of your local network.

...JRF...

[Vincenzo Restuccia]

See http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90685/B2355-90685_top.html&con=/hpux/onlinedocs/B2355-90685/00/00/63-con.html&toc=/hpux/onlinedocs/B2355-90685/00/00/63-toc.html&searchterms=ntp&queryid=20010503-015111