The Strengths and Limitations of Traditional Oracle Migration Methods

There’s an old saying: Insanity is doing the same thing over and over while expecting different results.


If you’re tired of spending your nights and weekends performing Oracle upgrades and migrations, struggling to minimize downtime and business impact, and worrying about what might happen if the migration fails, it’s time to shake things up. You don’t have limit yourself to old habits and old tools that don’t deliver the results you need. To get different results — better results — you need new approaches and new tools.

For example, the traditional way to reduce the impact of a migration on the business is to schedule resource-intensive tasks during times of low activity. But before you just accept all those long evenings and weekends in the office, look into newer technologies, such as near real-time replication, that can minimize the migration’s impact on the business — and your personal life.

Lest we throw out the baby with the bathwater, let’s take a hard look at the traditional methods for performing upgrades and migrations and determine whether and when they are helpful:

  • Export/import utilities and Oracle Data Pump — The most straightforward option for moving data between different machines, databases or schema is to use Oracle's export and import utilities. But, boy, talk about manual, time-consuming and error-prone. Plus, these utilities can be used only between Oracle databases and require significant downtime. Oracle Data Pump is a step up, offering bulk movement of data and metadata. But it still works only between Oracle databases and still requires significant downtime. Let’s keep looking.
  • Oracle database upgrade wizard — This wizard enables in-place upgrade of a standalone database. But it’s hardly a general-purpose solution, since you can upgrade only one single instance database or one Oracle RAC database instance at a time, and the source database version must be or above for upgrade to 11g or 12c. Next.
  • Oracle transportable tablespaces (XTTS) — XTTS enables you to move tablespaces between Oracle databases, and it can be much faster than export/import. So far, so good. But XTTS moves your data as it exists; any fragmentation or sub-optimal object or tablespace designs are carried forward. Wouldn’t it be better to be able to clean things up as you go?
  • Cloning from a cold (offline or closed) backup — Cloning a database is a means of providing a database to return to in the event an upgrade does not succeed. While having a failback plan is a critical piece of the puzzle, it’s hardly a complete upgrade or migration strategy. Moving on.
  • Manual scripts — Ah, custom scripts. The first time, they seem like the perfect answer. No migration tool to license or learn, and you can tailor the migration or upgrade to meet your exact needs. But if you’ve gone down this path, you know that the process of creating, testing and running custom scripts is complex and requires significant time from skilled IT professionals with expert knowledge of your applications. And most of the time, it doesn’t enable you to avoid the dreaded downtime. Isn’t there a less manual approach?
  • Online options — Online upgrade and migration options include traditional remote mirroring solutions, Oracle RMAN, Oracle transportable databases and Oracle Data Guard. But if you’ve tried any of these options, you know that they all have significant limitations. For example, the transportable database feature can be used to recreate an entire database from one platform on another platform — but that’s just one of many migration and upgrade scenarios you face. You need a comprehensive approach that reduces both costs and the downtime that impact the business.

In short, while each of these tools has value in certain specific scenarios, all of them are complex or resource-intensive, require lengthy downtime of production systems, or work only for Oracle databases. Fortunately, you don’t have to limit yourself to these traditional tools. In my next blog, I’ll explain why investing in an enterprise tool is a smart alternative.

You can also learn more in our new e-book, “Simplify Your Migrations and Upgrades: Part 2: Choosing a fool-proof method and toolset.