The purpose of this migration strategy is to enable the migration of a SQL Server database or logical group of SQL Server databases with a small window of downtime. This strategy uses Microsoft SQL Server with Always On availability groups to move critical SQL Server resources that are currently in Oracle Cloud Infrastructure-Classic (OCI-Classic) environments to Oracle Cloud Infrastructure. This same strategy is applicable to other clouds or even from your on-premises data center.
The architecture looks similar to the following diagram. The basis of the strategy is to use SQL Server Always On availability groups to move the databases that are mission-critical or too large to fit into the current downtime allotted for the migration. You build an Always On availability group between two or more SQL Server databases that reside in an OCI-Classic region and an Oracle Cloud Infrastructure region. Because SQL Server Always On availability groups handle one or more databases in a single availability group, ensure that you build your availability groups in a logical way that facilitates the best migration of the database with the least amount of downtime for the database.
Diagram 1: Architecture for Migrating SQL Server Databases from OCI-Classic to Oracle Cloud Infrastructure
This strategy use five phases of migration: Discover, Analyze, Plan, Migrate, and Post-Migrate.
In the Discover phase, you determine what the current environment contains and how it’s built. You can use the OPCMIGRATE tool to interrogate the OCI-Classic environment. The output report shows the number of instances and block volumes, and provides an overview of the current network topology. This information is the basis for building the new SQL Server environment in the new Oracle Cloud Infrastructure tenancy.
For more information about OPCMIGRATE, see Run Oracle Cloud Infrastructure Classic Discovery and Translation Tool to Generate Reports.