Database Migration

How to move your Exadata Cloud Service Databases to X9M with Zero Downtime

Introduction

Oracle constantly introduces new Exadata Platforms providing higher performance, lower latency, extended storage, and optimized software and networking. The latest Exadata X9M generation is available on-premises, cloud@customer, and public cloud. AND, it comes at the same price as the previous generation!!! It is as simple as this:

higher performance + same price = reduced cost

By delivering higher performance at the same price as the previous generation, Exadata X9M enables customers to reduce the costs of running transactional workloads by up to 42 percent, and analytics workloads by up to 47 percent.

In Oracle public cloud, the commitment for an Exadata Infrastructure is 48 hours. Yes, hours, not months. So if you are running your Oracle Databases on older generations in the cloud, why not move them to the newest X9M??? High effort? Long Downtime?

Neither of which! This blog post discusses migrating your databases to the newest Exadata generation EASILLY and with ZERO DOWNTIME.

Data Guard with Exadata Cloud Infrastructure

Indeed, the solution is straightforward: use Oracle Data Guard.

To enable Data Guard by clicking a button via Cloud Tooling, looking at the documentation, the primary and standby databases must be in the same compartment, have identical database versions, and have both Exadata system shapes. The latest one is significant. It says, “both Exadata system shapes,” i.e., both use Exadata Cloud Infrastructure. There is no restriction on the Exadata model (X6, X7, X8, X8M, or X9M). For example, the primary database can be on X7 while the standby is on X9M.

Let’s discuss two scenarios (actually three). As an example, we assume a migration from X7 to X9M.

No Data Guard in place yet

If you are not using Data Guard for your database yet, then the steps are very straightforward:

  1. Provision a new X9M Exadata Infrastructure.
  2. Enable Data Guard and choose the standby to be on the new X9M.
  3. Switch over! The database on the X9M becomes the primary.
  4. Terminate the standby (the former primary running on the older X7).
  5. Repeat steps 2 to 4 for all databases running on the older X7.
  6. Terminate the X7 Exadata Infrastructure.

Done!

Data Guard is already in place

Looking again at the documentation, the Cloud Tooling is limited to one standby database for each primary database. Hence, here we need to distinguish between two cases:

One Standby provisioned via Cloud Tooling

Suppose you run a primary and one standby provisioned via Cloud Tooling on the older platform. In that case, you will need to go through the following steps to migrate to the newest X9M using automated Data Gaurd deployments:

  1. Provision two new X9M Exadata Infrastructure.
  2. Terminate the standby database on the older X7.
  3. Enable Data Guard and choose the standby to be on the first X9M.
  4. Switch over! The database on the first X9M becomes the primary.
  5. Terminate the standby (the former primary running on the older X7).
  6. Enable Data Guard and choose the standby to be on the second X9M.
  7. Repeat steps 2 to 6 for all databases running on the older X7.
  8. Terminate the X7 Exadata Infrastructure.

All steps can be done using Cloud Tooling.

Consideration: When the standby is terminated, the primary will not be protected by any standby. For small databases, this might be a very short period of time. For larger databases, it might take longer. In any case, you need to calculate the risk.

One or more Standbys provisioned manually

In case you needed a specific configuration that is not (yet) supported by the Cloud Tooling and decided to build your Data Guard environment manually, then to keep the example simple, while having one standby:

  1. Provision two new X9M Exadata Infrastructure.
  2. Create a second and a third standby on the first and second X9M.
  3. Switch over to the standby on the first X9M! The database on the first X9M becomes the primary.
  4. Terminate the two standbys on the older X7.
  5. Repeat steps 2 to 4 for all databases running the older X7.
  6. Terminate the X7 Exadata Infrastructure.

Your primary database is protected by at least one standby database at all times. However, it takes more effort to build the Data Guard environment manually instead of using Cloud Tooling.

Zero Downtime

During switchover, which usually takes less than a minute when appropriately tuned, neither the primary nor the standby are available, so how to reach zero downtime?

Implement (Transparent) Application Continuity and make this database downtime transparent for the application. Even for running transactions, the downtime will appear as a short brownout to the application without the need to re-connect and re-execute any statements. It’s all done automatically by Application Continuity.

Conclusion

Moving to the newest Exadata Platform enables you to benefit from the higher performance at the same cost. Oracle Data Guard makes the transition easy and with no or minimal downtime. The automation provided by Cloud Tooling simplifies the process tremendously but comes with some restrictions if you are already running a Data Guard environment.

The Multitenant Architecture with PDB Cloning and Relocate provide further options to move your databases across environments with minimal downtime. Stay tuned!

Further Reading

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