On 21/06/2019 17:14, Markus Robert Kessler wrote:
> I am running some Raspberries, "Zero Wifi", with Raspbian (Stretch) for
> getting data out of some BME280 sensors. Every 10 minutes the sensors are
> queried, the data processed and sent to a (cgi) web interface to store
> the values on a webserver.
>
> For stability aspects I'm doing a reboot once per night via crontab, and,
> as shown in my router's logfile, this reboot and sign in into Wifi again
> takes less than one minute. So far, everything ok

I've got 10 Raspberry Pi's doing temperature logging with those and
similar I2C and 1-wire sensors, and I've never needed to reboot for
stability. If you are needing to do this, something is very wrong.

> But, every few weeks, the machine doesn't return from reboot.
>
> In the internet router's logfile I see that the machine has signed off,
> but does not sign in again into wifi. It will stay offline / dead.

It will be probably an issue reconnecting to the router. Reboot it again
and look in /var/log/syslog or /var/log/syslog.1 for the messages logged
between the last two reboots.

I found one of my Pi Zeros wouldn't reconnect to the router after a
power failure, but would do after power cycling just the Zero. Not sure
what the issue was as I re-imagined from one which didn't do this.

> If you remember the discussion I started some weeks ago, see
>
>      Subject: "Is Kingston knowingly crappy?"

If you suspect a card failure, do a sudo dmesg -H after boot and look
for evidence the the filing system is being repaired. But if the
corruption is bad enough to stop it booting once, it usually wont come
back up the second time either, without the card having to be repaired
in another Linux system. Which is why I suspect networking.

So:-

1) Reboot less
2) Look at the logs to see what happened
3) Compare with one that does work

---druck

--- SoupGate-Win32 v1.05