Oracle GoldenGate: The Challenges of Maintaining Zero Downtime During Upgrades

As the Internet continues to facilitate and speed up business transactions, the well-being of a number of industries is highly dependent on how strong, available, and reliable their network connection is. Financial companies must stay constantly open during trading hours, healthcare providers always require access to patient data, and retail outlets need to check and update their inventory after every sale.

Even the slightest amount of downtime for mission-critical databases can spell a significant loss of revenue for businesses in these domains. According to a 2011 survey by IT intelligence firm IDC, for example, companies in the financial services industry lose an average of nearly $10,000 per hour of downtime. Apart from lost revenue, downtime also negatively affects consumers’ opinion of your company and harms your business reputation.

Like overworked, fatigued employees who can’t spare the time to go to the doctor, these companies are often unable to schedule upgrades and maintenance to improve the availability of their database. The question then becomes: how and when can you have extended downtime windows and planned outages?

Fortunately, there are solutions to this apparent dilemma. By forming a plan of action well in advance, you can minimize the amount of downtime that your applications need in between disconnecting and reconnecting to databases.

One of the most popular tools in this regard is Oracle GoldenGate, an application for real-time capture, routing, transformation, and delivery of data across a variety of heterogeneous business systems. This post will give a brief overview of some of the challenges of getting zero downtime when completing upgrades and migrations, and discuss how GoldenGate and other strategies can maximize uptime.

The Challenges of Getting to Zero Downtime

Because in-place database upgrades do require some degree of downtime, any business seeking to avoid downtime and planned outages must perform a rolling upgrade instead. However, such an arrangement requires you to carefully consider how you’ll deal with a number of thorny technical challenges, including:

• Instantiation: During instantiation, the source data is copied and loaded into the target database. Throughout the migration, GoldenGate must make sure that the two databases are synchronized. This is particularly difficult when the target database is located on a different platform, or the source database has multiple terabytes of information to deal with. Testing the instantiation process with GoldenGate before using it in a production environment is highly recommended.

• Failbacks and Backups: Once you’ve upgraded or migrated to your new solution, you should still have a failback strategy in case you experience instability or performance issues, so that you can continue to service your customers seamlessly. While using your new database, you should continue to perform the same transactions on your old database as well so that you can quickly and easily switch over if necessary.

Final Thoughts

Although it’s entirely possible to use GoldenGate for achieving zero downtime, by no means is it necessarily easy. If you need assistance with a zero-downtime migration or upgrade of your own, contact an experienced Oracle partner who can help you through the process at every step of the way. For more detailed information on maximizing the use of GoldenGate, download our white paper, Top 9 Challenges of GoldenGate – and How to Solve Them.