Why am I getting this as an error

I have a flow to catch errors.
This morning I saw there were a few. Yes, something was happening, but why I got this error is confusing.

{"delay":"18000","payload":"2019-8-1 07:39:18 up 27 minutes\n","_msgid":"a9dafd22.a65de","_event":"node:94f35468.443b9","time":"2019-8-1 07:39:19","filename":"/media/pi/9020-9C27/logs/last_alive.db","error":"2019-8-1 07:39:18 up 27 minutes\n","topic":"ERROR_REPORT/TelePi/Local Readings/undefined","ttl":0,"_queuetimestamp":1564609159433,"_queueCount":11}

Why is it an error?

I am not seeing anything "wrong" with it.

The "thing that was happening:
When I got up, that machine's LED was flickering.
Looking at my dashboard, it was not responding to pings.
It wasn't connected to my WAP either.

I rebooted it. (Alas power cycle.)

Somewhere along the way the USB stick I have plugged in became read only.
I tested it and couldn't write to it.
I unplugged it and checked it on my main machine. It wasn't.
Plugged it back in, and all was sweet.

As I was "leaving", I saw that there was a flow error detected.

That's what I saw/got.

"topic":"ERROR_REPORT/TelePi/Local Readings/undefined"

Undefined usually ends up as an error.

1 Like

Yeah, ok.

That explains it.

The USB stick decided to become /dev/sdb1 rather than /dev/sda1 as it was before I unplugged it, or it became read only.

And wasn't there for a while as I was testing if it was read only on my other machine.