Oracle Database Migration to OCI FAQ
Getting started
What is Oracle’s strategy for database migration?
Oracle is committed to providing a simple, automated, and nondisruptive upgrade and migration path from every version of our Database to the latest versions and platforms. Our migration methods handle a wide spectrum of operational needs, from traditional offline backup and restore to more sophisticated online zero downtime operations.
Where can I find specific information about Oracle Database migration?
The first link below provides an overview of migration steps, planning advisors, illustrations of prebuilt migration method workflows, and their component technologies. You’ll find that each migration method has an overview, reference architecture, technical step-by-step guides, Oracle LiveLab walkthroughs, and documentation.
Learn more at these reference sites:
Terminology
What is the difference between a migration and an upgrade?
A database upgrade, such as upgrading from Oracle 19c to Oracle 23ai, updates the database software system and associated customer metadata but leaves customer data in place. Alternatively, a database migration moves data onto a new platform, such as migrating from on-premises servers to Oracle Database Cloud Services on OCI and Cloud@Customer.
Typically, migrations from older to newer versions, across operating systems, and character set migrations also require upgrades. However, there is some flexibility in the sequence of performing upgrades; they can happen before, during, or after a migration. This sequence decision will be based on both business and technical factors as described in the Oracle Database Upgrade Guide (PDF) and the Cloud Premigration Advisor Tool.
What are Oracle’s migration methods?
Business continuity is a key driver in choosing a logical or physical migration method.
| Business continuity | Logical method | Physical method |
|---|---|---|
| Online | ✓ | ✓ |
| Offline | ✓ | ✓ |
| Optimizes migration flexibility | Optimizes migration speed |
Online methods allow applications to remain operational during the migration. After an initial load of older data, newer data is captured in real time and then incrementally applied to the target database. At an appropriate point in time, a final switchover occurs, and the migrated target database becomes the operational database.
In an offline method, applications are not operational, and the database is migrated in one operation.
Data movement choices offer a tradeoff between backup/recovery speed and flexibility. The physical method is based on minimal to zero downtime fault-tolerant recovery capabilities using Recovery Manager and Oracle Data Guard. While this is the fastest method, it also requires that the source and target databases share identical characteristics, such as versions or character sets. The logical method is based on more flexible export and import capabilities, allowing for database configuration and version differences as data moves from source to target. Logical methods use Oracle Data Pump and Oracle GoldenGate.
Both physical and logical migrations also have a consequential performance impact based on how they write data to storage. The physical method reads and restores data by storage blocks, retaining gaps within the database files. This is efficient for backup/recovery speed, but not ongoing operational performance. The benefit of the logical method is that records are written contiguously—eliminating gaps. Since optimal performance is to have contiguous space to minimize random reads, the logical method has this advantage.
See this blog for additional technical discussion.
Strategy
What are the typical migration use cases?
There are many business and technical reasons to migrate databases, such as lowering the cost of ownership with automatically scaling resources or reducing business risk by increasing administrative and security automation. With Oracle Databases, migrating from on-premises to the cloud offers many managed service options, such as Oracle Base Database Service (Standard Edition or Enterprise Edition), Oracle Exadata, Oracle Autonomous Database, and Oracle Cloud@Customer.
| Cloud use cases | Reduce TCO | Reduce business risk |
|---|---|---|
|
|
|
How do I choose the best migration strategy?
The best migration strategy considers business and technical planning factors. Oracle offers automated solutions that simplify and streamline upgrade and migration workflows using embedded Oracle utilities, Oracle Database options, and supporting products. DBAs can also engineer their own migration workflows using the same Oracle Database utilities. Oracle planning advisors recommend the best migration method for nearly every scenario. And remember, Oracle and its partners are great resources to help you choose the best strategy.
| Planning advisors | Business factors | Technical factors |
|---|---|---|
|
|
|
What should my target database be?
Your best target database should match your operational, economical, and cost of ownership requirements. Typical requirements include minimizing disruption to current operations; improving performance, scalability, and disaster recovery; and reducing overall TCO and runtime hourly costs.
On one hand, you can simply migrate to an equivalent cloud service for your on-premises platforms, such as Oracle Base Database Service or Oracle Exadata Cloud Service. Or you can upgrade your database operating platform and take advantage of Oracle Exadata, the industry leader in transaction processing, database consolidation, and data warehousing, or Oracle Autonomous Database on the Exadata platform, adding more automation and lowering your cost of ownership.
Compare Oracle Cloud Database solutions to match your requirements to the appropriate database and platform and then fine-tune your choices with the database service advisor.
Is there an efficient way to evaluate the migration complexity for my entire database estate?
Yes. Oracle Estate Explorer catalogs and analyzes your database estate and securely evaluates its technical characteristics for migration to the Autonomous Database platform. You can evaluate your database estate behind your firewall without sharing any data or metadata with Oracle.
Common questions
What is the difference between Recovery Manager and Data Pump for transferring data as a migration method?
Oracle Recovery Manager (RMAN) is the Oracle Database backup, restore, and recovery utility. To achieve optimal performance, source and backup databases share many identical attributes. One of its key migration-oriented features is that it can capture incremental backups (changes made to the source database after the backup process has begun.) RMAN is the faster data transfer option due to block-level backup-recovery operations and is known as a physical migration method.
Data Pump is used to export and import data offering migration flexibility over migration performance. Unlike RMAN, once you start the export (backup) process, new transactions at the source are not captured. Also unlike RMAN, logical methods do not require identical configurations, which means that migrations can include upgrades. Known as a logical migration method, Data Pump moves data more slowly than RMAN but rewrites records sequentially to storage, compressing space and enabling faster SQL performance. Data Pump can be used in conjunction with GoldenGate to enable an online, logical migration method.
Is Real Application Testing or SQL Performance Analyzer useful in migration workflows?
Yes. Oracle Real Application Testing is an Oracle Database option that’s useful for validating migrations and is available independent of Enterprise Manager. It includes SQL Performance Analyzer and Database Replay. Licensing is required when using this option with on-premises databases. Refer to licensing information, Section 1.4, Table 1-15 under Oracle Real Application Testing.
In addition, Enterprise Manager includes a complementary Real Application Testing management pack that has five key capabilities: Database Replay, SQL Performance Analyzer (SPA), Workload Analysis, Database Migration Planner, and Database Migration Workbench. Find Real Application Testing management pack licensing information here.
The Enterprise Manager database migration workbench embeds SQL Performance Analyzer into its migration workflows. If Real Application Testing is present, then the menu options for SQL Performance Analyzer within Enterprise Manager database migration workbench becomes available.
Learn more about Real Application Testing and other migration tools for Oracle Autonomous Database in this blog.
Can I bring our on-premises database licenses to OCI?
The Bring Your Own License (BYOL) program offers comprehensive financial and functional incentives that enable you to spend less and do more as you migrate your database licenses to OCI Database cloud services. License transfer is designed to help you modernize your Oracle investments with improved price-performance and a lower total cost of ownership. Oracle Support Rewards is a complementary benefit that offers annual support credits for every dollar spent on OCI. Oracle also reduces migration risk with automation and services from Oracle and third parties.
Learn more in the Oracle PaaS and IaaS Universal Credits Service Descriptions and the BYOL FAQ (PDF).
What is the simplest migration path to Autonomous Database?
All complexities aside, the simplest path is an offline, logical migration method that uses the free OCI Database Migration service. Embedded within this online service is the Cloud Premigration Advisor Tool that specifies source database preparation tasks.
An exception to this is if you already license Oracle Enterprise Manager because you also have access to Enterprise Manager Migration Workbench. The migration workbench offers a complete migration workflow and uniquely includes Oracle Real Application Testing to validate resulting SQL performance on the Autonomous Database target. A Real Application Testing license is required.
In either case, if you have more than a few databases, use Oracle Estate Explorer to analyze your entire database estate. The analysis will prioritize migrations based on databases that require the least effort to migrate. This tool also recommends actions to prepare your databases for migration.