Test migration to decomposed setup using GitLab Reference Environments

The migration to decomposed setup was tested on development environment and fresh Omnibus installs using a Google Cloud VM. For development, some random data was inserted, resulting in a 45Gb database. So we have a gut feeling for the time it takes to migrate but we should validate that against more realistic scenario's

We can test migration to decomposed setup using one of the reference architectures.

• Setup a GitLab instance in single database setup
• Create test data: GPT Data Generator
• Migrate to two database setup and track the time needed.

We can then give more realistic downtime estimates

References:

• GitLab Performance Tool
• GitLab Environment Toolkit. We probably don't need a full blown GitLab setup, since migration will require downtime. But PostgreSQL host should be realistic concerning memory, disk size and CPU

Follow up from suggestion by @tkuah