Syncthing is not a good solution for a one time transfer. It is likely slower as the other solutions here.

It’s a docker volume. In this case it is managed by docker, but it is outside the container.

To have it save everything on your normal filesystem, it should be possible to just edit the docker compose file (I have not tried that)

Well you point the docker to some external data. You do never store the documents inside the docker. (Because it would get lost when it is updated)

It is comparable to the way Immich works.

How about Telegraf -> influxDB -> Grafana?

For monitoring from my phone (iOS) I use ServerCat which I really like. It can show the status of multiple servers at a glance and provides detailed information and a SSH terminal if needed.

Yes exactly.

If what you said was true, my secondary Pi-hole wouldn’t have to respond to any queries. But it in fact gets quite a lot of them. As the other poster has said, it is about 80/20 for 1st and 2nd pihole. Sometimes the ratios are different, depending on the time of day (don’t ask me why….).

That’s where having 2 also comes in handy. If one goes down it will still work as if nothing happenedy

If you have a friend with unlimited home internet, maybe you can just install a raspberry pi there and use that as a vpn server?

+1 for nodered

As there are currently bo other suggestions: I know that Audiobookshelf has support for non-audio books as well and it will sync progress. I have not used this functionality and don’t know how good it works for ebooks.