| RE: -EXT-Re: [chrony-users] Re: chrony losing sync with timeserver and never recovers |
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I had a similar type of problem using the release Chrony 2.x under RHEL 6 using only 2 time sources.
All looked good at the start but eventually the problem showed up.
If I recall my research, it had something to do some type of time source window situation.
If the sources' +/- differences windows did not overlap chrony quit trying to go back into sync.
I was polling much more frequently than you were.
***** ***** *****
Michael D. Parker
General Atomics – ElectroMagnetics Systems Division (EMS)
Michael.d.parker@xxxxxx <<<<< NOTE: Remember to include my middle initial >>>>>
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-----Original Message-----
From: Bill Unruh [mailto:unruh@xxxxxxxxxxxxxx]
Sent: Thursday, October 19, 2017 8:23 AM
To: chrony-users@xxxxxxxxxxxxxxxxxxxx
Subject: -EXT-Re: [chrony-users] Re: chrony losing sync with timeserver and never recovers
I am certainly confused by the log. The GPS and the PPS have never delivered a valid ntp to chrony. What happened 463 days ago?
When was this system started?
Or have you edited these responses, not showing us the complete picture?
Ie, are there other servers which are being polled? It may be that if there is no response from a server for N poll periods, chrony gives up and stops polling. I no longer know chrony well enough to say that this is what happens or not.
On Thu, 19 Oct 2017, Brendan Simon (eTRIX) wrote:
> Hi chrony-users,
>
> Anyone know why chrony would stop polling time servers? maxpoll is
> supposed to be 1024 (17 minutes) max, but I my system polls initially
> and then seems to stop polling servers completely. The example below
> shows 463 days with no response from 2 servers.
>
> Chrony 1.30 on Debian 8 (Jessie)
>
> Thanks, Brendan.
>
> ______________________________________________________________________
> ______
>
> On 17/10/17 2:24 pm, Brendan Simon wrote:
> I have a number embedded systems that are located in remote
> areas that need to be up 24/7 for logging of data via a 3G
> internet connection. The systems are ARM based and running
> Debian 8 (Jessie) with chrony installed as the ntp client.
>
> The systems sync with 2 ntp servers (`tic.ntp.telstra.net` and
> `toc.ntp.telstra.net`) on boot. I know this because (a) there
> is no RTC on the system, and (b) the application does not start
> until the system date is > 2015 (i.e. not the startup of default
> 1970).
>
> For some reason chrony loses sync with the servers and never
> recovers. I have system times that are out by minutes !!
>
> # chronyc sources
> 210 Number of sources = 4
> MS Name/IP address Stratum Poll Reach LastRx
> Last sample
> ===========================================================================
> ====
> #? GPS 0 4 0
> 10y +0ns[ +0ns] +/- 0ns
> #? PPS 0 4 0
> 10y +0ns[ +0ns] +/- 0ns
> ^? tic.ntp.telstra.net 2 10 0
> 463d -14ms[ -15ms] +/- 44ms
> ^? toc.ntp.telstra.net 2 10 0
> 463d -23ms[ -24ms] +/- 79ms
>
>
> As can be seen, the servers have a state of '?' and haven't
> recieved data in 463 days !! yet I can ping them ok, and if I
> restart chrony all is good again.
>
> The 3G modem can have problems and are reset (powered down and
> up) whenever internet connectivity is lost (detected by pings
> not responding). And 3G connectivity is not the most reliable.
>
> The interesting parts of the config are:
It would actually be more helpful if you gave us all the information. You do not know what is happening, so how can you be sure that these are the only "interesting" commands in your chrony.conf?
> server tic.ntp.telstra.net iburst
> server toc.ntp.telstra.net iburst
>
> makestep 1000 -1
>
> initstepslew 30 0.au.pool.ntp.org 1.au.pool.ntp.org
> 2.au.pool.ntp.org 3.au.pool.ntp.org
>
>
> What causes chrony to not retry servers?
>
> Is there a config setting I need to always try these servers?
>
> I notice the `online` and `offline` settings. Do I need to
> explicitly tag servers as `online`? I presume that's the
> default.
>
> Do I need to explicitly tag the servers as `offline` before
> powering the modem up and down? I thought leaving them online
> would be ok. The only downside is it may take a little longer
> to get the time back in sync, right?
>
> But they can only get back in sync if chrony is talking to the
> servers.
It might help to tag them as online when the 3g comes back up.
>
> Thanks,
> Brendan.