[chrony-users] Re: chrony losing sync with timeserver and never recovers

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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:

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.

Thanks,
Brendan.



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