[ntp:questions] ntpdate works, but ntpd doesn't (reach = 0)
David J Taylor
david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Thu Feb 12 07:46:33 UTC 2009
Nero Imhard wrote:
> Martin Burnicki wrote:
>> Why shouldn't ntpd be run e.g. on a laptop?
>> And surely this results in the question which has been discussed here
>> several times: why does it takes so long for ntpd to adjust an
>> initial tiny offset of a few milliseconds?
> In my understanding, ntpd was designed as a tool to discipline clocks
> of systems that need (or need to provide) very accurate time, and not
> as a general-purpose clock-setting tool.
> The requirements that would mandate the use of full-blown ntpd are
> mainly found on systems that stay up and connected for long stretches
> of time (time servers, measurement and monitoring systems, loghosts,
> file servers, etc.).
> There may well be examples of laptop use cases that require full-blown
> ntpd and where periodic setting using sntp is unacceptable, but I
> think they are rare.
> For this reason, I also think that shortening the time it takes ntpd
> to do its initial adjustment is not very relevant to its (presumed)
> design goals.
I certainly expect to run NTP on my laptops. Why should I put up with an
inferior SNTP, loose the ability to retain the drift value between boots,
or have to learn how to configure two different pieces of software? On
the other hand, providing that the time on the laptops is correct to
within a second, I'm happy. I'm not looking for much better than 100ms
I view NTP as a general purpose tool which should be automatically fitted
to /all/ systems, but I am willing to accept that it doesn't work as well
if the system is not permanently switched on.
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