Cache Eviction
The process of removing entries from a cache when it's full. Common policies: LRU (least recently used), LFU (least frequently used), FIFO (first in, first out).
What is Cache Eviction?
The process of removing entries from a cache when it's full. Common policies: LRU (least recently used), LFU (least frequently used), FIFO (first in, first out).
Cache Eviction is a foundational concept that sits in the Caching Strategies area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Cache Eviction" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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See also
Related glossary terms you might want to look up next.
Caching
Storing frequently accessed data in a faster storage layer so you don't have to fetch it from the original (slower) source every time.
Redis
An in-memory data store used as a cache, message broker, and database. Blazing fast because everything lives in RAM.
Memcached
A simple, high-performance distributed memory caching system. Stores key-value pairs in RAM. Simpler than Redis but less feature-rich.