[ntp:questions] ntpd, boot time, and hot plugging

Steve Kostecke kostecke at ntp.isc.org
Wed Feb 2 18:08:39 UTC 2005

On 2005-02-02, Brad Knowles <brad at stop.mail-abuse.org> wrote:

> At 8:48 AM -0600 2005-02-02, Kenneth Porter wrote:
>>  There's been some discussion on the Fedora-devel list about ways to
>>  speed up booting for workstations. One of the things that slows down
>>  the boot process is waiting for an initial network time sync. I'd
>>  like to solicit opinions on how to organize the interaction between
>>  ntpd, the OS, the boot scripts, the network interfaces (which may
>>  come and go; think mobile devices), and possible hot-plugged local
>>  time sources.
>  The problem is that there are many services which really need proper
> time sync in order to operate correctly.


> But beyond the standard mechanisms to speed up the initialization
> process of starting ntpd (e.g., using "iburst" on all the server
> configuration lines in your /etc/ntp.conf, etc...), I don't see any
> other ways to make this process faster.

My informal tests show that ntpd needs somewhere between 7 and 20
seconds to intially set the clock (using 'ntpd -gq'). It would be
reasonable to assume that starting ntpd with '-g' will take roughly the
same amount of time.

We need to keep in mind the fact that we're talking about workstations,
not servers, and that 'ntpq -g' can, and usually does, run in the

Steve Kostecke <kostecke at ntp.isc.org>
NTP Public Services Project - http://ntp.isc.org/

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