Weighted rendezvous hashing picks replicas deterministically and peer-equally without a central allocator — later hardened for failure domains. Teaches: content-hash-based placement, weighted rendezvous hashing, deterministic stable sort, failure domain filtering.
Systematic defensive coding: nil-safety, numeric overflow guards, resource lifecycle discipline, panic recovery at every boundary, and concurrency safety under -race.
Chain, Splay, and Primary-Splay replication — and the metrics-driven controller that switches between them at runtime.
Identify every object by its SHA-256 content hash — server-side dedup, verify-on-read, and a path that later mounted a filesystem. Teaches: content addressing principles, single write chokepoint, Bolt/Sentinel patterns.
A scaleless-gossip ring: SWIM-style failure detection, discovered-peer dialing, and ALIVE/OFFLINE restoration — momo’s nervous system.
How momo started as a file-replication playground in Go and grew into a distributed content-addressed object store.