Why we enabled Geo on the staging environment for GitLab.com

What this post added

This post details the enablement of GitLab Geo on the GitLab.com staging environment. It covers the rationale for testing Geo at scale, the setup process including selective synchronization and Gitaly shard configuration, and challenges encountered with PostgreSQL 9.6 and Foreign Data Wrappers. It also highlights bug fixes and future plans for end-to-end test automation and PostgreSQL HA configurations on Geo nodes.