[ntp:questions] iburst

Richard B. Gilbert rgilbert88 at comcast.net
Mon Nov 27 03:13:19 UTC 2006

terrypearl wrote:

> Richard B. Gilbert wrote:
>> terrypearl wrote:
>>> Added "iburst" to the server line in /etc/ntp.conf as:
>>> server 0.north-america.pool.ntp.org iburst
>>> server 1.north-america.pool.ntp.org iburst
>>> server 2.north-america.pool.ntp.org iburst
>>> I understood that adding the 'iburst' would spee synch on boot.
>>> Unfortunately, it hasn't. It still takes anywhere from 3 to 5 minutes 
>>> to synch.
>>> Is there a way to reduce the synch time to seconds instead of minutes??
>> Not really.  Even with iburst it takes something like twenty seconds 
>> to collect the information necessaray to START synchronizing the 
>> clock. The maximum slew rate of 500 parts per million means that it 
>> takes a while to correct any error.  I think that your "3 to 5 
>> minutes" applies to a "warm start"; e.g. starting with a good drift 
>> file.  A cold start takes something like thirty minutes to get tight 
>> synchronization.
>> This is all relative.  If you start ntpd with -q and use iburst you 
>> will probably not be off by more than 100 milliseconds.
>> If you need to be in tight synchronization at all times, don't ever 
>> shut down!!!  If your O/S requires frequent reboots, change to a 
>> better one.
> Not shutting down uses more electricity - since I am paying the bill on 
> that instead of my employer, of which I have none being on disability 
> and a fixed income which gets relatively smaller every year, I prefer to 
> keep my costs as low as possible. Do you have any more wise-ass remarks 
> on how to spend my money????
> Running Linux Fedora Core 5. Do you prefer Windows???
> It doesn't require reboots - just shutting down daily when I am not 
> using the machine.

Then learn to live with a clock that may be off by a 100 milliseconds or 
so.  If you NEED the exact time to better than 100 milliseconds, then 
you may have to make some sacrifices.

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