Would like to ask if it's ok to use a raspberry pi running bitcoin/lightning node, and connect the USB miners (with bitcoin merch USB hub) to it?
or is it recommended to have a separate raspberry pi for the miners?
idk about any official recommendations but i compiled cgminer on the latest build/image of mynode. I've been running it on there for 3 weeks now with no issues but i did need to disable tor. I also needed to install tmux [don't recall if it was already installed] to properly exit cgminer while keeping it running in the background.
note - i haven't actually spun up the lightning node yet locally but I should do it soon. Still need to set up BTC Pay. I just enabled the electrum server so RPC explorer and mempool are working and those are also running with no issues. RAM usage was at around 30-40% on an 8GB Pi 4 if I recall correctly. I don't think it's been over 50% but I guess if it does then you might run into issues with a 4GB Pi. Running taproot [bitcoin core 22] and have been able to locate a tx i sent to myself with the new taproot address type so it's pretty cool to be able to do that thru a GUI + mine and have that controlled thru the same device. (shoutout to the futurebit guys for the inspiration on that lol.)
i wasn't able to get it working at all with umbrel. cgminer compiled successfully on the umbrel image but the USB port never identified any miner or hub. i haven't tried on the latest version yet though.