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ZDM and How We Migrated to OCI in 6 Weeks

Migrating an on-premise database to the cloud within a limited timeframe can be a challenging endeavor. I had a High Education Client that put us to the challenge of migrating their Dev/QA and Prod Environments to an Exadata Cloud@Customer (ExaCC) environment in under six weeks. In this blog post, I’ll talk about a couple of points on how Oracle ZDM (Zero Downtime Migration) enabled this swift transition.

 

Architecting the Solution

Architecting the Exadata Cloud@Customer (ExaCC) VMs prior to the arrival of the hardware was one of the most critical pieces of this migration. By carefully designing the migration architecture, we anticipated potential challenges, optimized the migration process, and by doing this, minimize downtime.

This involved factors such as network connectivity, storage configurations, and application dependencies. 

 

Install and Configure ZDM Environment

The second thing we needed to do prior to the arrival of the ExaCC, is to prepare the ZDM environment. You can download ZDM here. Once downloaded we configured the ZDM environment by providing the necessary details such as the source and target database connection information, network configurations, and authentication credentials. This includes setting up the ZDM configuration file with the appropriate parameters, we could already do this as we had architected the Virtual Machines (VMs) prior to this.

 

Configure Source and Target Environment

We had to ensure the source database is configured correctly and accessible to ZDM. Set up the required connectivity and permissions for ZDM to capture data changes from the source database. We also had to configure the necessary networking, storage, and authentication settings to establish connectivity between ZDM and the target environment, as well as provide a shell database in the ExaCC. Last but not least, we had to verify the connectivity between ZDM, the source database, and the target environment.

 

Pre-Migration Tasks

As the timeframe of this migration was short, we made sure that we captured the SQL Tuning Sets (STS) on the on-prem environment so that in case any execution plan regressed, we could use SQL Plan Management to allow us to stabilize the system. From the migration standpoint, ZDM is equipped with pre-migration assessment capabilities. It performs an analysis of the on-premise database and identifies potential migration challenges. This evaluation helped us identify potential issues prior to the execution of the migration, like identifying the difference of patches between on-prem and ExaCC, or that the on-prem environment had a different compatible parameter for the version it was using.

 

Start the Migration

Once the pre-migration is validated, we initiated the migration process by executing the appropriate ZDM commands. We made sure to monitor the progress of the migration and address any issues or errors that may arise during the migration process. 

 

Perform Post-Migration Validations

After the migration was completed, we conducted post-migration validations to ensure the migrated database is fully functional and performing as expected. Making use of the previously captured STS to stabilize the system and make this a successful migration.

Migrating an on-prem database to an ExaCC in under six weeks can seem like an ambitious goal. However, Oracle ZDM empowered us to plan and achieve this objective with confidence and efficiency. By automating the database conversion, enabling near-zero downtime for this particular client, and providing validation capabilities, ZDM allowed us to perform a seamless transition within the desired timeframe. I can say with confidence that ZDM helped us to accelerate the migration journey and enables our clients to quickly leverage the benefits of the ExaCC. I will say, embrace Oracle ZDM and expedite your on-premise to ExaCC migration today.

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