Do some Pi Zeros need to run slow so they don't freeze up after a while?

Question

I've used a number of Pi Zeros and some seem to need to run slow. The symptom is they freeze after a number of hours or a day or so. I'm using the Zero not the Zero W. I'm running the camera. I've read posts on problems booting Pi Zeros, and cases where they were inadvertently clocked at less than the default 1 GHz, but this is different.

In my case, when I look at syslog after a crash, all is fine until, for no apparent reason, nothing is recorded for a while and the next thing you know, the system reboots. (I have a hardware watchdog that resets the system after about 30 minutes of inactivity.) Such a crash usually indicates a hardware problem with the cpu, so the question is, do I need to underclock it ? If so, what parameters should I use ? The cpu temperature is at the upper end of the normal operating range. I have plenty of power.

I'm going nuts over this. Can anyone shed some light on it ?

Thank you in advance.

Answer 1

Your question (or something like it) is asked frequently here :) That said, please don't take this to mean that all or most RPis freeze up frequently!

Unfortunately, there isn't a pat answer for the issue. Think about other computers you've owned... no doubt you've seen them freeze also (hopefully not as frequently as you've described). Temperature is sometimes a cause, but it could be that the temperature has affected performance of your SD card, or another component. And SD cards themselves seem prone to cause problems. Power supplies are also on the list of "usual suspects". If there were one (or a few) reasons that explained freezes, there wouldn't be so many hits for that search term! :)

You've done the right thing by inspecting the logs, but I've not seen much to suggest that the log files are typically reliable informants for what causes freezes.

Given that there are multiple causes for "freezes", the "scientific method" may lead you toward a solution: Consider devising some tests that attempt to isolate the variables. For example, is it always the same Pis that freeze? If so, have you tried changing SD cards? If you find no correlation for these variables, what about temperature? Do the Pis that freeze (most frequently) run hotter than those that don't? Checking temperature periodically with a cron script may provide useful data. The software that you're using may be a variable of interest... do the Pis that freeze most often run software that's different from the ones that don't?

Once you feel you've isolated a variable (potential cause), specific questions here will yield greater benefit. For example, "Is there a 'rule of thumb' for underclocking my RPi to reduce temperature?" Or if you want to try that (underclocking) yourself, this earlier Q&A might help

Hope that helps.