Checklist for documenting a medium to large scale system architecture

Some items that can help you document a undocumented legacy system.

• Identify common points of failure in the architecture.
• Identify uptime maintained in the last year (in 9s).
• Identify maintainer/dev team size.
• Identify specific version numbers of SDKs, APIs and packages used.
  • Identify if updating SDKs can break the system.
• Get entire server inventory list with os details.
• Create documentation for the deployment strategies.
• Create as many flowcharts/visual representations of the modules as possible. Way more than textual documents.
• Make notes. Make lots of notes. Don't discard/delete anything. When you are actually documenting things, make sure all the notes you have made are checked for inclusion.

Acknowledgements

• Big thanks to folks on developersIndia and The Engineerin Org discord for their inputs.