So I keep reading that etcd is heavily reliant on disk writes, something RPi SD cards are bad at. I was planning to get a third RPi4 and run clustered, but maybe it’s a no-go? SD card writes are already making the system slow, even though all persistent volumes are on NAS.
Yep, that’s accurate. etcd could bring those Pis to their knees, especially if the control plane comes under load.
Thank you! I will most likely just add a dedicated master then.
I wish RPi5 would come with embedded eMMC 
Is it possible to move the etcd writes to a new location? Related question: is it possible to pass any config to the embedded etcd at all? I’d like to fiddle around with the --unsafe-no-sync option too.