So you already figured that syncing the whole file on each state change isn't going to work. Here are two alternatives
CLN / eclair already has it, LND is going to put more work into it this year and next: the move from boltd db to postgres (and SQL). It's on the roadmap, and pg allows synchronous replication across clusters, which is ideal for disaster failover.
if you want to try something on your own, just for tinkering with the idea: remote raid solutions like drbd 👉 apt install drbd8-utils are offering just that. You mount a remote server, ideally through a tunnel, and setting up drbd. As a result, the channel.db states get written to both devices at the same time, just like a local raid
Of course the latter has high demand on your network availability and latency. But it's better than nothing in case of catastophic failures.
apt install drbd8-utilsare offering just that. You mount a remote server, ideally through a tunnel, and setting up drbd. As a result, the channel.db states get written to both devices at the same time, just like a local raid