Caching

/ˌɛl ɑː ˈjuː/

noun — "evict the item not used for the longest time."

LRU, short for Least Recently Used, is a cache replacement and resource management policy that discards the item whose last access occurred farthest in the past when space is needed. It is based on the assumption that data accessed recently is more likely to be accessed again soon, while data not accessed for a long time is less likely to be reused. This principle aligns closely with temporal locality, a common property of real-world workloads.

/ˌsiː-diː-ˈɛn/

n. “A network that delivers content at the speed of thought.”

CDN, or Content Delivery Network, is a distributed network of servers strategically placed across the globe to deliver web content—such as HTML pages, images, videos, and scripts—quickly and reliably to users, regardless of their location. Instead of all requests going to a single origin server, a CDN caches content at edge locations, reducing latency, load times, and the chance of downtime.