I'm using ElastiCache Redis and storing small piece of data (~5-10MB) in it. Everything works perfect for a while and then suddenly it responds lot longer than usually (like 2000ms instead of 100ms). Most of actions that I'm doing is simple select single entry from Redis and then providing it to client. I noticed this problem only in benchmarks, not in real usage.
According to Google and StackOverflow it can be related to Redis Persistence, but I found that persistence is disabled in group options of ElastiCache.
I used redis-stat to monitor stuff in Redis, and seems like there are regular CPU usage spikes by system every n-minutes. Anyone knows what kind of thing can cause such problem?