After a few months, I've migrated everything to my cluster, removed the old MacBook, even got 2 versions of #FoundryVTT running and a couple other fun services.
The problem is even though #GlusterFS was the right choice in the moment, *arr apps absolutely HATE network storage. #SQLite is the culprit, and the devs for #Lidarr, #Radarr, #Sonarr, and others appear completely uninterested in switching away from SQLite. I would prefer #MySQL, but evidently, even though this issue repeatedly comes up, folks like me who want to run *arr apps on a swarm are edge cases.
So, I could restrict each app to a specific node, which I don't want to do because a couple of my nodes will randomly stop working and require me to manually restart them. Or, I can continue to put up with DB corruption, which is proving to be a real pain.
Or search for another solution to replace *arr? Truth be told, I use Lidarr the most and it isn't super great at what it does.