Redis Best Practices

Priority: P0 (CRITICAL)

• Security:
• Access Control: Use Redis 6.0+ ACLs (

  ACL SETUSER

  ) to restrict commands by user/role.
• Encryption: Always enable TLS for data-in-transit (standard in managed Redis like Azure/AWS).
• Dangerous Commands: Disable or rename

  FLUSHALL

  ,

  KEYS

  ,

  CONFIG

  , and

  SHUTDOWN

  in production.
• Connection Resilience:
• Pooling: Use connection pooling with tuned high/low watermarks to avoid connection churn.
• Timeouts: Set strict

  read_timeout

  and

  connect_retries

  to handle transient network saturation.

Guidelines

• Key Design:
• Namespacing: Use colons to namespace keys (e.g.,

  app:user:123

  ,

  rate:limit:ip:1.1.1.1

  ).
• Readability vs Size: Keep keys descriptive but compact; avoid keys > 512 bytes.
• Commands & Performance:
• O(N) Avoidance: Use

  SCAN

  instead of

  KEYS

  . Use

  UNLINK

  instead of

  DEL

  for background reclamation of large keys.
• Lua Scripting: Prioritize

  EVALSHA

  for atomic logic; ensure scripts pre-loaded to save bandwidth.
• Massive Range: Limit

  ZRANGE

  ,

  HGETALL

  , and

  LRANGE

  results with offsets/limits.
• Memory Management:
• Eviction Strategy: Use

  allkeys-lru

  for general caches and

  volatile-lru

  for mixed persistent/ephemeral data.
• Lazy Freeing: Enable

  lazyfree-lazy-eviction

  and

  lazyfree-lazy-expire

  (Redis 4.0+) to offload cleanup from main thread.
• Monitoring: Watch

  Used Memory RSS

  vs

  Used Memory Dataset

  . Large fragmentation suggests need for

  MEMORY PURGE

  or scaling.

Anti-Patterns

• No sole truth in Redis: Always persist critical data to durable primary database.
• No large blobs: Split values > 100KB into smaller keys or use Hashes for field access.
• No JSON for objects: Use

  HSET

  for object fields to enable O(1) access without full decode.
• No TTL-less keys: Set TTL or eviction policy on all non-permanent keys to prevent unbounded growth.

References

• Best Practices Guide
• Checklist