Exactly, I thought you would just end up with some single point of failure elsewhere and you’re complicating your setup greatly. If you really need more reliability, it might perhaps be better to get one of the big Firebricks which may iirc have two power supplies ?
I’ve been looking into various linux apps, but I need to exclude the ones with a graphical UI as I only want a daemon, I don’t want to be looking at something and in any case I can’t as I have no monitor. I have two other problems.
1. The app has to work with no internet connection, because the firebrick will be dead, that’s the whole point. And so no DNS for example. That’s going to kill some apps unless they have been specially written with this problem scenario in mind, or unless internet access requirements such as DNS queries just do not ever come up in the process of doing whatever the daemon/server process does. One could perhaps try to keep the DNS cache permanently filled if you know the required queries, which is perhaps ok. It’s a bit horrible second guessing the behaviour of the app though. If you did the naughty trick of probing the Firebrick by quoting its domain name then that would keep the cache filled but then the service process would fail if initially there’s no DNS.
2. How on earth do you send a message from the monitoring process on the Raspberry Pi to my iPad over an isolated LAN, no internet access. You also need something on the iPad to watch for that message and give me an iOS notification, which is an OS call or similar that produces a visible message and optionally rings a bell, and the notification is kept in a list so that you can go and look back and see that the Firebrick died some while ago. so that’s actually an additional pair of problems to solve, making three in all.