NTP does have the ability to run without a drift file, so if one is not specified, I believe you would be running without it.
The ntpd behavior at startup depends on whether the frequency file,
usually ntp.drift, exists. This file contains the latest estimate of
clock frequency error. When the ntpd is started and the file does not
exist, the ntpd enters a special mode designed to quickly adapt to the
particular system clock oscillator time and frequency error. This
takes approximately 15 minutes, after which the time and frequency are
set to nominal values and the ntpd enters normal mode, where the time
and frequency are continuously tracked relative to the server. After
one hour the frequency file is created and the current frequency
offset written to it. When the ntpd is started and the file does
exist, the ntpd frequency is initialized from the file and enters
normal mode immediately. After that the current frequency offset is
written to the file at hourly intervals.
If you want to see if you have a drift file you can try the following and see what comes up:
Not sure if you need to or not, but you can also configure this simply by adding:
driftfile /var/lib/ntp/drift or some other path, to
The drift file is only actually read when
ntpd starts. So essentially, if the file path isn't set, it will put you into that
initialization mode for the
15 minute period each time the system reboots or the service is restarted, but once that is accomplished it should run as normal.