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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] PPS Synchronization Verification
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Mon, 2 Nov 2020 15:42:50 +0100
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On Mon, Nov 02, 2020 at 01:48:28PM +0000, Chang, Benjamin wrote:
> So I added the offset and am now getting this. Does this mean I'm successfully synced to the PPS since the NTP is selectable (by the '-') but is instead syncing to the PPS?
> [cid:image002.png@01D6B0F4.AEC938E0]
Please include the output in the mail instead of attaching screenshots
of a terminal. Some people have text-only mail clients and it's also
wasting storage and network.
> So it appears that chrony can only sync to one thing and not both (a ref clock and a server). Does it syncing to my PPS mean that its getting the time/date from the ntp, but the seconds from the PPS?
A PPS refclock cannot be "locked" to an NTP source. The NTP source
just provides the initial synchronization and then PPS can take over
using the seconds from the local clock.
> Also, I did notice that occasionally it appears I am losing synchronization to the server/refclock by the following image:
>
> [cid:image001.png@01D6B0F4.EE2EED90]
>
> Is this because I have the polling be too fast? Do you know what could be causing this?
If the PPS signal has only one pulse per second, then yes, polling at
-6 would cause the source to appear unreachable.
--
Miroslav Lichvar
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