Migrate Oracle workloads to Azure

As part of your cloud adoption journey, you must migrate your existing workloads to the cloud. Oracle workloads are similar to other workloads and require a methodical approach to ensure a successful migration. For more information about migration methodology, see Cloud migration in the Cloud Adoption Framework. This article describes unique constraints and considerations that are specific to Oracle workloads.

The Oracle migration process

You should continually reassess your infrastructure requirements to improve performance and reduce costs by using the relevant type of service for your workload. For example, if you plan to move your workload to Oracle Database@Azure, ensure that the SKU that you select meets your requirements. Similarly, if you move your workload to Oracle on Azure Virtual Machines, ensure that the virtual machine (VM) sizes meet your requirements. For more information, see Capacity planning for migrating Oracle workloads to Azure landing zones.

Review the migration resources to define your Oracle to Azure migration process. You can also:

• Verify Azure subscription quota limits: Ensure that the quota limits in your Azure subscription accommodate the target VM sizes that you choose if you migrate to Oracle on Azure Virtual Machines.

• Identify a deployment model: Automate the deployment of solution components as much as possible by using infrastructure as code (IaaS), continuous integration and continuous delivery (CI/CD) pipelines, and other DevOps practices.

• Determine application dependencies: Ensure that migration activities are minimally disruptive.

• Identify data capacity: Identify the amount of data to migrate and assess the current available network connectivity capacity from on-premises environments to Azure. Use this information to determine if you can copy the data directly from on-premises environments to Azure. You might need a physical data transfer appliance like Azure Data Box for the initial data load.

• Determine availability requirements: Determine the workload availability requirements because they might affect the migration tools that you can use.

For Oracle Database@Azure, make sure to:

• Verify that the Oracle Database@Azure solution is available in the region where you want to deploy the solution. For more information, see Available regions.

• Consider required database changes when you move from on-premises environments to Oracle Database@Azure. Migration might involve some changes to the database tablespaces and schema. For more information, see Migrating Oracle databases to Exadata Cloud Service.

Oracle migration workload-specific activities

The following section describes the migration process in more detail. The steps aren't necessarily sequential. You can perform some steps in parallel.

• Assess the source and destination system versions: Assess whether the on-premises operating system versions, application versions, and database versions are the same as the versions that you plan to use on Azure.

  • If you need to update one or more resources, update them before migration to avoid complicating the migration process.

  • If your on-premises database runs on a large endian operating system, for example Oracle Solaris, IBM Advanced Interactive Executive (AIX), or Hewlett Packard Unix (HP-UX), the database migration process includes an endian conversion. Azure supports only little endian operating systems. From a tooling perspective, this support limits the number of options when you consider what tool to use for the migration. Specifically, you can't use Oracle Data Guard, Azure Migrate and Modernize, or any other file copy method. Migration methods that are compatible with endian conversion include Oracle Data Pump Export, Oracle Data Pump Import, Oracle Cross Platform Transportable Tablespaces (XTTS), or data replication utilities such as Oracle GoldenGate, Quest SharePlex, and Striim.

  • You can modernize or migrate on-premises application servers depending on requirements and compatibility. For more information, see Cloud adoption scenarios.

• Assess the workload availability requirements during the migration process: If you need to minimize workload downtime, then migration methods such as the Data Pump Export feature, the Data Pump Import feature, or Azure Migrate and Modernize might not suit your workload. In that case, you can do the following three-step process:

  • Use Oracle Recovery Manager (RMAN) to back up and then restore the entire database in Azure. Perform an endian conversion through XTTS if necessary. The result is a database that's a point-in-time copy of the on-premises source database. For more information, see Transporting data across platforms.

  • Use Oracle Data Guard to synchronize the newly restored database in Azure with the source database if both sources are little-endian format. You can't use Data Guard if the migration involves big-endian to little-endian conversion. Instead, use a SQL-based data replication utility such as Oracle GoldenGate, Quest SharePlex, or Striim to synchronize the newly restored database in Azure with the source database.

  • After you synchronize the target database in Azure with the source on-premises database, you can schedule a cutover. A cutover shuts down the source on-premises database and flushes the last few transactions to the target database in Azure. Then you can open the target database in Azure as the new source database. A cutover can take as little as a few minutes, depending on the sync method that you use.

  • Depending on the migration approach that you choose for application services, you might need to complete several application service tasks before you fully migrate the application to Azure.

  • Consider using Oracle Zero Downtime Migration (ZDM) for the migration process. For more information, see Zero Downtime Migration.

• Assess required licenses: Your database might require various licenses depending on the migration tooling. For instance:

  • Oracle Data Guard requires Oracle Database Enterprise Edition.

  • Oracle GoldenGate requires Oracle GoldenGate licenses.

  For more information about Oracle licensing on Azure, see Licensing Oracle software in the cloud computing environment.

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