AIX > Tips & Techniques > Migration

Tips for Migrating Oracle Databases to IBM AIX

IBM recently interviewed Jim Dilley, Distinguished Engineer with IBM’s Advanced Technical Skills-Oracle Solutions team, about migrating Oracle databases from HP-UX Itanium to IBM AIX. This comes on the heels of Oracle’s recent announcement that it is halting development on HP-UX/Itanium versions of its products.

Q: What makes migrating Oracle databases from HP/UX Itanium to IBM AIX easier than moving these databases to Linux on x86?

A: HP/UX Itanium to AIX is big endian to big endian, whereas HP/UX Itanium to x86 is big endian to little endian, which is more complicated and time-consuming. Oracle has done a great job of making it easier to move from one big endian machine to another big machine. Customers can use Oracle tools to migrate the data, circumventing the endianness conversion when possible. Customers can also use Oracle tools to facilitate the endianness conversion if it is needed.

Q: How complex is the Oracle database migration process?

A: There are a variety of ways to migrate a relational database. One toolset Oracle has enabled is called RMAN, or Recovery Manager. Oracle database administrators use it every day for general backup and recovery. Using the standard recovery mechanisms, customers can simply back up an offline database on one system and restore it on another system. There are a variety of other options for more time-critical situations, including Veritas Storage Foundation Portable Data Containers, SharePlex for Oracle or Oracle’s GoldenGate. I think customers and the industry overall have been pushing for more transportability between platforms. Oracle’s response to that has been to remove architecture-specific information from its databases, and to provide tools to customers to make the process much less complex.

Q: How long does the HP/UX Itanium to AIX Oracle database migration process take?

A: That varies based on the size of the database, the method chosen, the size of source and target hardware, the size of the tables, how the database might be partitioned, and a variety of other factors. It can vary from a matter of hours to a much longer period of time for larger and more complex databases.

Q: What are the mechanics of an HP/UX Itanium to AIX Oracle migration?

A: If a customer is doing a platform migration for an Oracle database, such as an HP-UX on Itanium to AIX on a Power platform, where both source and target platforms are big endian platforms, the easiest process is to execute an offline full backup and restore using RMAN. If the customer can take production down, they can take a copy of production and restore that copy to IBM Power Systems using RMAN. After that, they would do integration, application and database integrity testing, row counts, schema checks—anything they would normally do to ensure database health on a new target environment—and then repeat this process several times to understand, address and alleviate any issues they uncovered. They would probably also build a punch list of the exact steps, and a detailed timeline of what they need to do during the production outage, as well as map out what things need to be done on the target side (if there are post-migration issues) once cutover is complete. Then they need to schedule the downtime window—which is almost always over a weekend day or over a full weekend—lock down the system and execute the cutover per the punch list-documented process and timeline. If the customer’s downtime window is small because they have a high percentage uptime requirement, they would probably look to use advanced tools for data replication, such as shadow table replication, GoldenGate or SharePlex.

Q: Should customers consider getting a database migration assessment? What does this entail?

A: Yes. Customers can get a free assessment from IBM, and we recommend it. This usually entails fact-finding conference calls and/or meetings on-site, after which IBM teams will usually run scripts on the source database to determine things like database size, row counts, numbers of tables and content of tables. This is all done in an effort to better characterize the environment in order to understand what issues might be encountered in migrating a specific database.

Tweet