Starting a new public server: Chrony or NTP?

Which software is preferred these days for a public NTP server? Chrony or good old NTP?

It doesn’t matter what you use.

Chrony is more advanced and has better time-management.

But ntpd has better support for time-devices like DCF.

It all depends on your plans.

If it’s a simple Stratum 2 server, then Chrony is the best choice.

For Stratum 1 it’s more complicated and depends on the driver you need.

In short, there is no simple answer unless we know more about the setup-plans you have.


Good question, I totally forgot to mention it is indeed going to be Stratum 2. I’ll look into Chrony!

IIRC ntp-refclock claims to allow chrony users the use of any (one?) of the classic ntp refclocks. shm, pps, gpsd-json, and local-clock would seem to be redundant though.

Also the NTPsec project exists along with other implementations.

Chrony can alter the Cmos-clock if you want it to be corrected.

# This directive enables kernel synchronisation (every 11 minutes) of the
# real-time clock. Note that it can’t be used along with the 'rtcfile' directive.

# Step the system clock instead of slewing it if the adjustment is larger than
# one second, but only in the first three clock updates.
makestep 0.1 3

Then I let cron do a

chronyc makestep

every hour to correct the cmos-clock.

No need for drivers or anything.

Chrony uses just a few clock-sources, not many like NTP.

In fact just GPS and PPS and HWclock-stamping and some other, but that is about it.
E.g. DCF77 with Chrony is just a nightmare to get running.

If you want to do Stratum1 with Chrony and you use GPS with or without PPS, then Chrony is the way to go.

But if you have other drivers/devices, then NTP is hard to beat.

For stratum2 they are both ok and easy to setup.

I find Chrony more forgiving and beter time management then NTP, but that is my opinion.

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