In Part 2 of a blog series, Ken Chen explores performance evaluations using MongoDB's Full Time Diagnostic Data Capture (FTDC) metrics and logs, highlighting the integration of the Keyhole tool with Grafana to visualize data and improve cluster performance. The blog details the installation and configuration process for Grafana, the use of Keyhole to analyze FTDC data, and methods for identifying performance bottlenecks and slow operations within MongoDB clusters. Common issues such as WiredTiger ticket depletion, disk IOPS limitations, and missing indexes are addressed, with solutions like adding indexes or increasing disk IOPS to enhance performance. Chen emphasizes the importance of understanding diagnostic data to diagnose and resolve issues, ensuring efficient database operations. The integration of Keyhole with Grafana allows for a comprehensive visual analysis, aiding in the quick identification and resolution of performance issues, thereby improving the overall health of MongoDB clusters.