Discord
How Discord Moved Trillions of Messages From Cassandra to ScyllaDB
Discord's careful, dual-write migration off Cassandra to ScyllaDB, and the parallel move to Rust, both driven by the same enemy: GC pause tails.
3 min read
Category
Discord
6 articles
Discord
Routing Millions of Voice Calls Through Discord's SFU Infrastructure
How Discord's voice chat scales using selective forwarding units, UDP-based media transport, and globally distributed voice servers close to users.
3 min read
Discord
Where Discord Reached for Rust, and Why
From swapping Go for Rust in the Read States service to speeding up Elixir's WebSocket handling, how Discord chose specific hot paths for a rewrite.
3 min read
Discord
Presence and Read States: Keeping Millions of Discord Clients in Sync
How Discord keeps online status and per-channel read state consistent across millions of simultaneously connected clients without collapsing under fan-out.
3 min read
Discord
Discord's First Big Migration: MongoDB to Cassandra for Messages
Why Discord outgrew a single MongoDB replica set for message storage and moved to Cassandra years before its later ScyllaDB migration.
3 min read
Discord
Why Discord's Gateway Runs on Elixir and the BEAM
How the Erlang VM's lightweight process model and fault isolation made Elixir the right fit for Discord's connection-heavy real-time gateway.
3 min read