Redis memory eviction deletes session data causing user logouts

Redis memory eviction policies automatically delete session data when memory limits are reached, causing random user logouts and authentication failures. Redis connection failures without graceful fallback cause application crashes.

Configure Redis eviction policy appropriately for session storage (avoid allkeys-lru for sessions). Implement graceful error handling that returns null on cache failures rather than throwing exceptions. Set retryDelayOnFailover: 100 and maxRetriesPerRequest: 3 for connection resilience. Don't let cache failures crash the application.