Troubleshooting Redis In-Memory Eviction Strategies (6316)

Technical Overview

Engineering breakdown of Troubleshooting Redis In-Memory Eviction Strategies (6316). Bare-metal hardware performance requires isolated kernel parameters, tuned memory allocators, and precise eviction policy selection to avoid latency spikes under memory pressure.

Eviction Policies

• volatile-lru - Evict least recently used keys with an expire set.
• allkeys-lru - Evict any key using LRU approximation.
• volatile-lfu / allkeys-lfu - Frequency-based eviction.
• volatile-ttl - Evict keys with shortest TTL.
• noeviction - Return errors on write when memory limit reached.

On bare metal, the vm.overcommit_memory and vm.swappiness sysctls directly impact Redis fork() overhead during RDB/AOF persistence, which in turn influences eviction latency.