Dead Pi
Well that's a first for me. A dead Pi, or rather a dead SD card. I have a RPi 2 in the loft connected to a DVB-T dongle and ADSB antenna which sends data to FlightRadar 24. It's been up there doing its thing for ages, but last night I received an email from FR24 that it had stopped sending data. As it turns out that was a very useful email because everything else was running fine.
It also logs temperatures from three 1Wire temperature sensors on the central heating pipes. As these are underneath the location of the Pi in the loft it was easier to run a wire down for the 1Wire sensors than cobble together another Pi and find a home for it away from the heat of the water cylinder and pipework. That logging and my network monitor indicated that all was apparently well and I had not noticed the FR24 status data indicated that the ADSB feed was down.
The Pi is fed via a PoE supply as I didn't want a wall-wart and mains socket up there and it makes it easier to reboot. I logged into the Pi fine ad rebooted it from the command line to see if that cured the ADSB issue in case it had simply lost the USB-connected dongle. But it never came fully back and would not even open the ssh port. It did respond to ping. Power cycling made no difference and by this time it was midnight.
This morning I made a new SD card and got it all back working (actually better as the card is the latest o/s now and the FR24 feed also has the MLAT option built in). So, some interesting and annoying observations:
The Raspberry Pi website now has a download package for the Mac which makes creating a new SD card image a doddle. Simply download and run it, stuff a blank SD card in and choose the options and wait.
Don't use the HDMI monitor, mouse and keyboard off your desktop PC when trying to get a Pi to work if you need to use said desktop PC at the same time! Yeah...
No matter how good your backups, if you cannot remember the name of an important file the backups are useless by themselves. D'oh.
But most importantly remember that you can mount a Pi SD card on a Linux box (and no doubt other systems) and access the files if the card still mostly works like mine did. Fortunately there were only two things on this Pi, the 1Wire code which is a five-line bash script and the FR24 package which basically installs itself from their download site. QED.