Load Balancer
A load balancer evenly distributes incoming traffic among web servers that are defined in a load-balanced set.
Database Replication
A master database generally only supports write operations. A slave database gets copies of the data from the master database and only supports read operations.
Cache Tier
The cache tier is a temporary data store layer, much faster than the database. The benefits of having a separate cache tier include better system performance, ability to reduce database workloads, and the ability to scale the cache tier independently.
Content Delivery Network (CDN)
A CDN is a network of geographically dispersed servers used to deliver static content. CDN servers cache static content like images, videos, CSS, JavaScript files, etc.
