What is the benefit of a relay cluster?
Can't there just be a DB and then the workers fetching from the DB scale up or down based on capacity?
I am somewhat itching to implement a relay-cluster ontop of this.
https://github.com/antirez/disque
Imagine: some servers just listening, others just constantly running generic spam filters, and some working to store and optimize, perhaps get stats or something... o.o
Discussion
Iunno! Just kinda shooting into the blue o.o
But, I would expect that work-balancing between nodes would improve efficiency and throughput. If Nostr grows, so do need the relays. They are the sole backbone of Nostr - the better (and faster) the relays, the smoother the Nostr experience becomes overall. By leveraging a cluster, work can be split and distributed, improving compute and resource usage. At least, in theory.
As for the DB, I think that kinda depends? AFAIK Discord uses a Cassandra Cluster precisely because of that - to improve access to and from the DB - so it acts monolithic, but really isn't. So they probably use replication and clustering within that Cassandra cluster as well.
But, that said, I am just spewing random thoughts into the world. Ya never know! Might strike gold. =)