Your question is Operating Cassandra and Solr. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Explain how you would operate and troubleshoot a Digicert-scale Cassandra and Solr deployment, including handling large partitions, mutations, backups and restores, repairs, compactions, and monitoring for read and write latency.