This document discusses performance testing an application with 100,000 concurrent users. It outlines some of the challenges with performance testing at scale on a single node. The proposed solution is to build and deploy the application, create load test slave instances, run a test plan against the new environment from the slaves, and then clean up by shutting down instances. Key lessons learned include issues found and fixed related to garbage collection and serialization, bottlenecks identified, and challenges scaling test clients. Performance testing is integrated into continuous integration to measure performance for each test case with each build.