On 14/10/2019 12:24, NY wrote:
> The lack of a battery-backed (or even capacitor-backed) real-time clock
> is a nuisance if the Pi reboots and there isn't an internet connection
> by the time the Pi needs it - if it takes longer for the router to boot
> and establish a connection than it takes the Pi to boot. I run a
> weather-station recording package (Cumulus) on my Pi and occasionally
> after a power cut the Pi has booted up with the wrong time (eg 30 or so
> minutes in the past) so I've had readings every minute marked with the
> wrong time which leads to a graph that goes back in time (!) until NTP
> eventually syncs the Pi's clock (*). It happens so rarely that it's not
> worth devising my own external battery-backed RTC solution, but it's
> annoying when I have to go in and hand-modify the times in the log files
> and restart the software so it reads and displays them on its graphs.

There are a number of RTC modules for the Raspberry Pi, which are ideal
for what you are doing. https://lmgtfy.com/?q=Raspberry+Pi+RTC

While you've got one of those on order, it is possible to configure NTP
to poll far quicker. See man ntp.conf minpoll and maxpoll.

---druck

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