Your company is shutting down their data center and migrating several MySQL and PostgreSQL databases to Google Cloud. Your database operations team…

Database Migration Service (DMS) is Google Cloud's recommended serverless tool for migrating databases like MySQL and PostgreSQL to Cloud SQL with minimal downtime. It is fully managed, which is ideal for a constrained operations team, and it automates the setup of continuous replication to keep the source and destination in sync until cutover. Alternatively, manually configuring replication from an external server is a valid method. This involves setting up the on-premises database as the source and the Cloud SQL instance as a replica. This approach also ensures continuous data synchronization, allowing for a minimal downtime migration. Both methods directly address the core requirements of the scenario.

A. This describes the result of the process in option E. "Replication from an external server" is the more accurate description of the action performed for migration.
B. A standard read replica in Cloud SQL is used for replicating data from another Cloud SQL primary instance, not from an external, on-premises source.
D. A cross-region read replica is a feature for disaster recovery or read scaling, creating a replica of a Cloud SQL instance in a different Google Cloud region.

1. Database Migration Service (DMS): "Database Migration Service is a serverless service that makes it easy to migrate your data to Google Cloud... It helps you migrate your MySQL and PostgreSQL workloads into Cloud SQL... with minimal downtime."

Source: Google Cloud Documentation, "Database Migration Service overview", Introduction section.

2. Replication from an External Server: "You can migrate data from an external MySQL or PostgreSQL server to Cloud SQL by using database replication... This process is also known as migrating using an external replica." This confirms that setting up replication from an external server is a primary migration method.

Source: Google Cloud Documentation, "Replicating from an external server", Overview section.

3. Distinction of Read Replicas: "Cloud SQL read replicas... A read replica is a copy of the primary instance that reflects changes to the primary in almost real time." The context throughout this documentation is replication from a Cloud SQL primary instance, not an external one.

Source: Google Cloud Documentation, "Replication in Cloud SQL", Read replicas section.