Define and setup a 25k reference architecture configuration

Steps:

• Stand up an additional reference environment that is initially set up identically to the 10k environment.
• Run 500RPS (2.5x the 10k RPS) against this environment and compare the resulting latencies to 10k results for the same GitLab version.
• Add appropriate nodes as needed to improve latency, retest as required.
• Continue to add nodes and retest until the latencies of this environment under 2.5x the load is comparable to the 10k environment latencies.

Acceptance criteria for certification (tentative):

• Latencies at 500RPS on the 25k environment should be less than 500ms, with the exception of known bugs affecting certain endpoints.
• Endpoints that have known bugs have issues created and fed into the Performance Grooming process.
• Documentation has been added to describe the 25k environment's configuration.

Diagram

• Google Drawing https://docs.google.com/drawings/d/1nBBdicbQe9Ekzwvkxio2HDhZOh7Bim3xaF2z3ZUtplc/edit

Documentation

• https://docs.gitlab.com/ee/administration/high_availability/#25000-user-configuration