Database Migration

Decision Tree for migrating Oracle databases to Oracle Cloud

Oracle provides different technologies and methods to migrate Oracle databases across platforms. This decision tree is intended to provide an overview of options available to migrate Oracle on-premises databases to Oracle Cloud Database Service (DBCS) or Oracle Autonomous Database. Before making the final decision, review the Oracle documentation for all prerequisites, restrictions, and recommendations.

Some of the characteristics and factors to consider when choosing a migration method are:

  • Character set
  • Endian format (Oracle Database Cloud uses Linux platform, which is little endian)
  • Database version
  • Data types
  • Acceptable downtime
  • Database size
  • Network bandwidth
  • Storage for data staging

Downtime

For this decision tree downtime is categorized as follows:

  • Long: Time needed for Data Pump conventional export and import.
  • Short: Time needed to copy the data files over the network or to create and apply the last incremental backup.
  • Zero: Time needed for switchover.

The actual time needed for “long” and “short” could vary from few minutes to several hours depending on database size and network bandwidth. In my opinion, if you can afford the time for export and import, go for Data Pump. It provides a very easy way and great options for moving only the data needed and start with a new, “clean”, and higher version database.

One-Click Migration

Oracle provides different tools to simplify the migration process. All steps to be processed manually are automated to be executed by one click to save time and effort:

Further considerations

  • Migrating to different target version: RMAN Backup/Restore requires same versions for source and target databases.
  • Database Editions: Data Guard requires EE.
  • Permitted features and options in Oracle Database offering.
  • Available features and data types in Oracle Autonomous Database. Check Oracle Autonomous Database Schema Advisor (Doc ID 2462677.1)
  • TDE is enabled for Autonomous database and all DBCS editions by default.
  • Using Data Pump encryption and RMAN encryption for backups.
  • Using PARALLEL and/or NETWORK_LINK in Data Pump for faster migration.
  • Using VPN Connect and/or FastConnect for fast, reliable, and secure data transport.
  • Using Storage Gateway to transport large amount of data to Cloud Object Storage.
  • Available migration methods for database releases older than 10.1.0.3.
  • Migration methods for small amount of data or limited number of objects: SQL Developer Copy, SQL*Loader etc.
  • Using remote clone or Unplug&Plug for 12.1 non-CDB source databases. Non-CDB is not available as a target in Database Cloud Service and will be desupported in 20c.
  • Migrating to 19c as it is the long term support release.

Further Reading

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