Easy Time Sync

Started by BrandyWine, September 24, 2025, 09:11:43 AM

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Try a CenterClick device:

https://centerclick.com/ntp/

Satisfied customer, nothing else. Works splendidly.

I use that as my "preferred" peer with the official time source for Germany as a fallback. Then distribute to all devices from my OPNsense.

I really do not understand why you refuse to run ntpd on every 24x7 up device. That's at least how it was intended to be done when the software was designed. And how I run it in my data centres with approximatly 100 machines. Of course we run ntpd on every single one of them.
Deciso DEC750
People who think they know everything are a great annoyance to those of us who do. (Isaac Asimov)

Quote from: BrandyWine on October 10, 2025, 10:58:19 PM[...]
In US we do have NIST WWVB 60kHz time carrier, supposedly very accurate[...]

The source is good, but the signal varies - although it penetrates structures pretty well. You also have to correct for location. GPS tends to be easier to deal with, if you can get a signal.

I have an old Ultralink 325 - the very last one they had. It's only supported by ntpd (that I know of). I haven't had it hooked up in some years, but one of these days I'll set it back up.

Quote from: Patrick M. Hausen on October 10, 2025, 11:10:01 PMTry a CenterClick device:

https://centerclick.com/ntp/

Satisfied customer, nothing else. Works splendidly.

I use that as my "preferred" peer with the official time source for Germany as a fallback. Then distribute to all devices from my OPNsense.

I really do not understand why you refuse to run ntpd on every 24x7 up device. That's at least how it was intended to be done when the software was designed. And how I run it in my data centres with approximatly 100 machines. Of course we run ntpd on every single one of them.
That's one of the amzon devices that start at $250(us). For home use that mean the antenna has to be in good location. It's too bad they didnt include a USB-A port and support 1-2 common USB mini wifi adapters, then it could be somewhat more flexible between location and network access.

As for ntpd, I just don't see any reason to leave it memory resident, anything I have that does NTP will do it to ntp.org or nist. An hourly ntpd -q is enough to keep fw time accurate. It's not stepping, only slew adjusts.

Not having a 123 listener there for 59min50sec every 1hr means less exposure (even if restricted by conf), and, less use of system resources, and it still accomplishes the same thing as running ntpd resident.

I know drift file can change with ntpd running all the time, so that is something I am looking at, not much info on how (or if) ntpd -q does drift file update functions, I know it reads the drift file, just not sure it will update that file, but I can check and see if value has changed. I know for sure using -q will not create a drift file.
Mini-pc N150 i226v x520, FREEDOM

Quote from: BrandyWine on October 10, 2025, 10:58:19 PM
Quote from: Linwood on October 10, 2025, 09:05:20 PMIf they are properly built.
I was looking at some GPS ntp units on amzon, they are built into small metal enclosure with long wired antenna, $300(us)+
No idea about those.  That's 5-10 times what some people spend doing it on the cheap, so definitely has more potential.

"You don't get what you don't pay for"   :)

Quote from: BrandyWine on October 10, 2025, 08:49:03 PM
Quote from: Kets_One on October 10, 2025, 06:26:24 PM2x GPS and 1x DCF77
Reconciliation of multiple sources is an interesting subject.

Are both GPS receivers using same GPS service?

GPS (receiver) is accurate to approx 100ns. Is the DCF77 broadcast any better?

Yes, both GPS sources are professional NTP appliances from Meinberg. DCF77 is not more accurate than GPS however, but I wanted some diversity in the time sources.
for example in case GPS reception is disturbed.
When bought these are quite expensive, but they are regularly offered on Ebay for a few hundred USD/EUR. Support from Meinberg is excellent. They still offer firmware updates for many of their NTP appliances, even many years after production. Highly recommended.
Deciso dec3840: EPYC Embedded 3101, 16GB RAM, 512GB NVMe

Quote from: BrandyWine on October 10, 2025, 01:23:27 AM
Quote from: cookiemonster on October 09, 2025, 11:59:24 PMbut my reasoning is on the other side of yours
If one needs fw to be NTP server, then by all means leave "it" memory resident.
I only want fw device to keeps it's own clock updated, and I don't run any NTP server anywhere locally.

I am curious about chronyd on your setup, can you post a "ps -aux |grep chronyd"

Sure.
penguin@OPNsense:~ $ sudo ps -aux | grep chronyd
Password:
chronyd  15768   0.0  0.1   26820   3700  -  I     3Oct25     0:06.49 /usr/local/sbin/chronyd
root     15797   0.0  0.0   22080   3108  -  I     3Oct25     0:00.30 /usr/local/sbin/chronyd
penguin  26228   0.0  0.0   13748   2004  0  S+   09:54       0:00.00 grep chronyd
Just the forked process:
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you have 16GB ram?
Mini-pc N150 i226v x520, FREEDOM

The mini pc host has 32 GB but this is a VM on it. It only has been given 6 GiB and 2 vCPUs.