How do you configure Redis for cache-aside pattern usage?

The cache-aside (lazy-loading) pattern keeps the application in control of when data is read from and written to the cache, with Redis itself needing minimal special configuration — the pattern mostly lives in application logic, with a few Redis-side settings that support it well.

# pseudocode for the read path
value = redis.get(cache_key)
if value is None:
    value = database.query(...)
    redis.set(cache_key, value, ex=300)  # cache for 5 minutes
return value

maxmemory 4gb
maxmemory-policy allkeys-lru

On the read side: check the cache first; on a miss, fetch from the source of truth (typically a database) and populate the cache with an appropriate TTL before returning. On the write side, the application typically writes to the database and then either updates or invalidates the corresponding cache key, rather than writing to the cache directly as the source of truth — Redis in this pattern is explicitly a derived, disposable copy, never the authoritative store. An eviction policy (as covered elsewhere) and sensible per-key TTLs are the main Redis-side configuration that keeps a cache-aside deployment healthy, since the pattern assumes cache misses are cheap and expected, not a failure condition.