Coursera, a leader in online education, leverages Amazon ElastiCache with Memcached as a read-through cache on top of Cassandra to support its extensive user base and course offerings. The platform employs Datadog to monitor ElastiCache's performance, ensuring the cache is effective in maintaining a high hit rate and preventing memory evictions that could impact application latency. Key metrics monitored include CPU utilization, memory usage, Get and Set commands, network throughput, and events to ensure that nodes remain balanced and efficient. Coursera's engineering team employs Datadog alerts to manage critical metrics such as eviction rates, available memory, and hit rates, using communication tools like PagerDuty and Slack for prompt notifications. By integrating Datadog, Coursera can visualize and correlate metrics across its infrastructure, enhancing the ability to quickly diagnose and address performance issues.