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 are 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 the main thread.
  • Monitoring: Watch

    Used Memory RSS

    vs

    Used Memory Dataset

    . Large fragmentation suggests a need for

    MEMORY PURGE

    or scaling.

Anti-Patterns

• No sole truth in Redis: Always persist critical data to a 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