How Discord Stores Billions of Messages

Discord continues to grow faster than we expected and so does our user-generated content. With more users comes more chat messages. In July, we announced 40 million messages a day, in December we announced 100 million, and as of this blog post we are well past 120 million. We decided early on to store all chat history forever so users can come back at any time and have their data available on any device. This is a lot of data that is ever increasing in velocity, size, and must remain available. How do we do it? Cassandra!