Its interesting to note that the the boweb-production servers of "www" don't have read-replicas (asynchronous replication) for read scalability. Anyone know why? Typically, one would use read-replicas to alleviate read workloads on the master.
Try systems companies (e.g. storage, networking) - you get to build products that leverage core CS concepts - algorithms, distributed systems etc. You also get a chance to use your investigative skills to debug problems like race conditions, memory leaks etc.