Scaling

Words

All learned. See them in History.

• Cache-aside

  The app reads from a cache such as Redis first; on a miss it reads the database, stores the result in the cache and returns it.

• CDN

  A network of servers around the world that keeps cached copies of your files and responses close to users.

• Load balancer

  A server in front of several copies of your app that passes each request to one of them, using a rule such as round robin or least connections.

• Read replica

  A read-only copy of a database that the primary keeps updated, usually asynchronously.

• Sharding

  Splitting one big dataset across several databases by a shard key, so each database (a shard) holds only its part.

• TTL (time to live)

  A lifetime in seconds attached to a cached value, a DNS record or a message; when it runs out, the copy is deleted or treated as missing.