how to use "ntpd" to emulate "ntpdate"?

[Rodolfo J. Paiz]

At 20:37 1/30/2004, you wrote:
>I missed the start of this thread, but does "ntpdate <server>" not do what
>you want? I run it here from a cron job every 2 hours, seems to work
>fine.

Here's the link someone posted explaining why ntpdate is being deprecated 
and why it's so inferior:

http://www.ntp.org/ntpfaq/NTP-s-config.htm

Of course, "inferior" means that your time may be off by as much as a 
second or so, which is fine for most of us but unthinkably awful for ntpd 
which usually keeps my server in sync by less than a millisecond. That 
difference in perception is why most of us see ntpdate as a useful thing 
but why the maintainers are going to kill it off.

Lest others read Michael's post as suggesting that an ntpdate run every two 
hours is a good thing for a /server/, I thought I should add some comments. 
Most servers should run ntpd in order to keep time synchronized as closely 
as possible, and most organizations should run at least one ntpd server to 
which their computers can synchronize. Please note that, in Michael's 
example, he is synchronizing to an /internal/ server so hitting it every 
two hours is just fine.

ntpdate every hour or two is great for clients connecting to an internal 
server, but it would not be a good solution for a server. This is partly 
due to accuracy issues, and partly since it generates fairly large traffic 
spikes for the public servers and causes an unnecessarily high amount of 
traffic and load for them. So be a good netizen, run one or two ntpd boxes 
on your network somewhere, and sync all other boxes to those.

And, if you /insist/ on using ntpdate regularly against public servers, PLEASE:

         1. Do not run as frequently. Update only once or twice a day at most.

         2. Set non-standard times. If a million computers all hit ntpdate 
at midnight, or every hour on the dot (1:00, 2:00...) the public servers 
are going to have huge problems. Set yours up to update at 3:37am and 
3:37pm or odd times like that.

         3. Rethink your strategy and try to stop doing regular ntpdate 
updates.


-- 
Rodolfo J. Paiz
rpaiz at simpaticus.com
http://www.simpaticus.com