Redis AOF fsync Latency Spikes: When Durability Becomes Your p99
Redis AOF can turn durability into p99 spikes: fsync pressure and rewrite fork CoW. Runbook to confirm, mitigate safely, and add guardrails.
#redis
7 posts
JWT Revocation Strategies: When Stateless Tokens Need State
User compromised, need to revoke JWT immediately. But JWTs are immutable. I compare allowlist, denylist, and short expiration with performance benchmarks.
Redlock vs PostgreSQL Advisory Locks: When You Don't Need Redis for Distributed Locking
Adding Redis just for distributed locks? PostgreSQL advisory locks might be enough. I compare both with failure scenarios and performance benchmarks.
Cache Stampede Prevention: Probabilistic Early Expiration (X-Fetch)
100 requests hit expired cache simultaneously. All 100 query the database. I implement the X-Fetch algorithm that refreshes cache before expiration without locks.
Redis Memory Fragmentation: When maxmemory Isn't Enough
Your Redis has 4GB maxmemory but RSS shows 6GB. OOM killer strikes. I explain jemalloc fragmentation with reproduction steps and activedefrag tuning.
API Idempotency: Designing Endpoints Resistant to Retries
Complete guide to implementing idempotent APIs. From Idempotency-Key through Redis locking to request processing state diagram.
Redis Cluster Slot Migration: Temporary Memory Explosion
Redis nodes OOMKilled during cluster rebalancing. The cause: slot migration copies keys to destination before deleting from source, temporarily doubling memory usage.