ALL
For a while, started getting the dreadful "skips" in WeeWX Graphs. Sure, and apologies to Tom & others, that I gave WeeWX the "usual suspects" eyes...
Tried to ignore at 1st, but later showed to be prominent and consistent, to the extend that my RPi4 could not even hold a SSH/Putty connection for long without rebooting itself...
Googling "RPi Crash/Reboot" will mostly only say that 99% its the power supply or USB cord to blame. Thus I switched both, many ways, and still same...
Maybe it's "software/OS" related: Burned an older, and "formerly stable" WeeWX, and still same...
Maybe it's "hardware": Changed RPi4 to a different, but similar and newer, RPi4, and still same....
Thus: good SD card (not the "cheapo"), good RPi4, good power supply & USB cable..., and still same...
Next... debugging strategies (which may be obvious to some, but took me longer in the learning process, and I post in case of guidance to others). In summary:
1) Keep a steady SSH connection from computer to RPi... and see if it maintains, or reboot/shutdown
2) Power supply/USB cable? (99%)
3) "# service --status-all"... What is running?!
4) Any extra interface, or mount?
5) Reboot RPi, stop installed services one-by-one
6) Stop unnecessary RPi/Raspian services (if headless, no need for X-Desktop, video, sound, blutooth, etc)
In my case, not necessary in the above order, but by command "# service --status-all", it showed that I had 'Monit" still running.
Monit is a monitoring service that I tried long ago as to keep a Watchdog upon WeeWX. Turned out, as it didn't accomplished what I was expecting, thought that I had removed already.... but not. Then 'Monit' (after OS updates) was the culprit... and now things back to normal after purge/remove...
On the "Silver lining of things", I cleaned-up a LOT of Raspian extra services that I didn't even knew it was running in the background or actually using... (and so should you).
Xant
PS: this is a repost, as right after posting it, my DD-WRT router died; thus, just to be fair as events been different and isolated, I deleted the above post till be sure; now fixed RPi, DD-WRT, etc... and WeeWX running as expected.