[ntp:questions] How is the BIG guys (Google. FB etc) DNS and NTP architecture

Jakob Bohm jb-usenet at wisemo.com.invalid
Wed Oct 21 07:55:14 UTC 2020

On 2020-10-21 05:47, William Unruh wrote:
> On 2020-10-21, CRasch Net <crasch at crasch.net> wrote:
>> Facebook is now using Chrony, you can read about their implementation:
>> Building a more accurate time service at Facebook scale
>> https://engineering.fb.com/production-engineering/ntp-service/
> Interesting. While I agree that chrony is more precise, I think that
> their results for ntpd are worse than they should  be. ntpd can
> certainly do better than 1ms scatter/accuracy (and chrony can do better
> than 100us.There is something weird about their network paths.) About 10
> years I ran a number of tests of chrony vs ntpd. and got about a fctor
> of 3-10 better, not 100. Interrupt latency/clock reading for chrony gave
> about 1us fluctuations.
> I find this whole thing about leap second smoothing to be a real farce.
> Just let the step occur instead of delivering the wrong time for hours.
> Or if you want, run your clocks on TIA not UTC and make the leapsecond
> conversion in the interpretation as is done for timezones. Would anyone
> advise leap day smoothing every 4 years so that we do not have trouble
> with our calenders?

Originally, that is what they did, they smeared the leap day over 2 
solar days.

For a smeared timescale, perhaps something could be created that
distributes UT instead of UTC, it would need an input file with the
same data used to transmit UT-UTC in the standard radio protocol
(see the ITU-R standard for UTC).  Plus some kind of NTP protocol
change to let clients know that the data incorporates the astronomical
wobble and may need polling at the right time to pick up the wobble.


Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded

More information about the questions mailing list