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skywatch
Posts: 46
Joined: Tue May 21, 2013 8:17 pm

Rpi 3B+ network crashing?

Tue Nov 12, 2019 12:14 pm

I have been trying to solve the issue of a pi 3B+ 'crashing' after a few days or weeks. :evil:

I have used various power supplies (3A and 6A) as well as different power cables.

The pi boots and runs from an SSD so should not be due to SD card corruption.

Today I found it had stopped responding to http and ssh again, so I went to investigate. I found it powered on but the network yellow and green leds on the network port were out. Looking at the pi itself the green 'ACT' led was flashing 7 times repeatedly. This is apparently because it cannot find kernel.img. :shock:

My question is how can a pi that has been running get into this state and what can I try to eliminate this issue?

Thanks for any help with this. :)

iznobe
Posts: 424
Joined: Sun Feb 05, 2017 4:14 pm
Location: Avignon , FRANCE

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 3:05 pm

skywatch wrote:
Tue Nov 12, 2019 12:14 pm
This is apparently because it cannot find kernel.img. :shock:

My question is how can a pi that has been running get into this state and what can I try to eliminate this issue?

Thanks for any help with this. :)
why do you think that ?

ejolson
Posts: 5136
Joined: Tue Mar 18, 2014 11:47 am

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 3:16 pm

iznobe wrote:
Tue Nov 12, 2019 3:05 pm
skywatch wrote:
Tue Nov 12, 2019 12:14 pm
This is apparently because it cannot find kernel.img. :shock:

My question is how can a pi that has been running get into this state and what can I try to eliminate this issue?

Thanks for any help with this. :)
why do you think that ?
It's possible that the Pi spontaneously rebooted and could not find kernel.img due to a corrupted state of the USB to SATA bridge.

The symptoms you describe sound like substandard power to me. I would suggest either running the SSD from a powered hub or buying a heftier power supply for the Pi.

What is the output of vcgencmd after the system has been busy for a few hours but not crashed yet?

For testing you need to simultaneously stress the CPU, SSD and network. To do this I would suggest a combination of iperf3, cpuburn and hdparm; however, other programs may help as well.

User avatar
skywatch
Posts: 46
Joined: Tue May 21, 2013 8:17 pm

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 4:12 pm

@ejolson

Thanks for the tips.

vcgencmd won't return anything on it's own, will it? :?:

Still, I have today changed the power connectors used on this and another pi that has had 'issues' recently. Maybe a batch of out of tolerance connectors? Only time will tell.....until then the mystery remains. ;)

ejolson
Posts: 5136
Joined: Tue Mar 18, 2014 11:47 am

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 5:27 pm

skywatch wrote:
Tue Nov 12, 2019 4:12 pm
@ejolson

Thanks for the tips.

vcgencmd won't return anything on it's own, will it? :?:

Still, I have today changed the power connectors used on this and another pi that has had 'issues' recently. Maybe a batch of out of tolerance connectors? Only time will tell.....until then the mystery remains. ;)
The documentation for vcgencmd is here:

https://github.com/raspberrypi/document ... cgencmd.md

You probably want the get_throttled option. I think anything other than zero indicates a problem. More information is available at the above link.

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skywatch
Posts: 46
Joined: Tue May 21, 2013 8:17 pm

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 5:37 pm

Thanks - after 5 hours running vcgencmd get_throttled gives 0x0 - So seems OK then ?

ejolson
Posts: 5136
Joined: Tue Mar 18, 2014 11:47 am

Re: Rpi 3B+ network crashing?

Tue Nov 12, 2019 5:52 pm

skywatch wrote:
Tue Nov 12, 2019 5:37 pm
Thanks - after 5 hours running vcgencmd get_throttled gives 0x0 - So seems OK then ?
Running idle and running under a stress inducing load are two very different things. Which did you do?

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