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Cloud migration: top tips for balancing cost and application performance

While cloud computing might have once been considered a fad, few IT administrators would see it that way today. Even before the coronavirus crisis, public cloud services had become a critical part of most organisations’ IT infrastructure. Now, with businesses facing significant disruption, the scale and flexibility offered by the technology has become indispensable.

Yet major misconceptions still plague the cloud computing sector. One of the most problematic is the notion that the technology is guaranteed to save companies money. Unfortunately, for many that is a false promise, and “bill shock” remains a common barrier to further cloud migration. In order to mitigate these risks, Quest produces a number of tools that database administrators (DBAs) can put in place to ensure they are getting excellent value for money while maintaining optimum database performance.

When it comes to migrating on-premises Oracle databases to the cloud, DBAs will face several questions: Which cloud service is the best fit for your organization? Which of your Oracle databases is best suited for a migration to the cloud? How will you monitor database performance and ensure scalability without blowing your budget? And, perhaps most important, will you really lower your Oracle licensing costs and avoid platform lock-in to any single cloud provider?

Given that not all workloads run better in the cloud, you must evaluate your current databases according to factors like application support, performance and importance to the business. You are likely to observe, for example, that some on-premises applications tend to slow down at month-end, when business analysts run reports that compete with normal transactions for database resources.

A logical solution is to run those reports against a cloud-based instance of Oracle Database Enterprise Edition (EE) to reduce the impact on the on-premises applications. Also, by migrating non-production databases used for QA and testing, you can minimize risk and replace Oracle EE licenses with less costly Oracle Standard Edition (SE2) licenses.

To maximize your flexibility and control over server configuration, you may choose to opt for infrastructure as a service (IaaS) from one of the main public cloud vendors. The resulting hybrid database environment will meet your short- and long-term needs for business modernization.

But cloud migration is not entirely risk-free. In addition to the operational risks of downtime and data loss is the financial risk of a mismatch between performance and cost. That is why Quest offers a complement of tools for reducing both operational and financial risks.

1. Pre-migration benchmarking with Benchmark Factory

One of the first tasks involved in any migration is to determine the appropriate cloud service subscription level. The service tier is the configuration of CPU, memory, storage and network that will scale properly and provide the expected performance after migration.

Although different cloud providers offer ways to right-size or calculate the optimum service tier, they are generally based on historical performance data, not on real-world database transactions. Wrong-sizing the service tier will likely mean sub-standard application performance and scalability or higher than anticipated subscription costs. Sometimes both.

In this step, you assess the difference in performance between an on-premises Oracle database and an Oracle database running in the cloud. Using Quest’s Benchmark Factory, part of Toad for Oracle DBA Edition, you can generate load and perform the same industry-standard test on both databases.

Once you’ve selected the type of test you want, Benchmark Factory will execute a scaleability test on the source on-premises database and the planned cloud database with an ever-increasing user load profile and compare the results in a graph, similar to the one below, showing transactions per second versus user load.

2. Pre-migration performance monitoring with Foglight for cross-platform databases

Before migration, it’s a good idea to monitor the performance of both the on-premises database and a similar database running in the cloud.

Benchmark Factory generates load on the on-premises and cloud Oracle databases. In this step, the SQL Performance Investigator (SQL-PI) feature of Foglight can compare the performance of both databases and perform deep-dive analytics on where the database is being stressed. The simple, apples-to-apples comparison highlights any significant differences in performance between on-premises and cloud databases as user load increases.

3. Pre-migration assessment with Toad for Oracle – sensitive data protection

As more DBAs become de facto data controllers, they find themselves on the front lines of sensitive data protection in their organizations. With the Sensitive Data Protection module of Toad for Oracle, you can locate the data you need to protect in your on-premises Oracle database schemas before migration. Once you locate columns of sensitive data, you can use Toad to apply Oracle’s encryption and redaction features, securing the data prior to migration. This selective approach will ensure you strike the right balance between database security and optimum performance and cost.

4. Migrating an Oracle database from on-premises to the cloud with SharePlex

Migrations often present an opportunity to upgrade to a newer version of Oracle or to a different operating system. And migrations from Oracle EE to Oracle SE2 in the cloud can result in lower database licensing costs. Our SharePlex tool facilitates migration by replicating data to cloud targets with no impact on business operations, minimal downtime and no data loss. SharePlex can support many other use cases post-migration including on-going data replication for HA, DR or offload reporting, load balancing, consolidation or even moving Oracle data between different clouds.

5. Post-migration benchmarking with Benchmark Factory

Will the Oracle instance in the cloud scale as transaction volume and demands on resources grow? To mitigate any performance issues ahead of time, DBAs run additional scalability tests using real-world transactions. Benchmark Factory performs a workload capture on the Oracle EE database running on-premises using Oracle Fine-Grained Access Control (FGAC) to capture database transactions.

Benchmark Factory then replays the captured workload on the Oracle SE2 instance running in the cloud and displays the resulting increase or decrease in performance. To test database scalability, it applies a scale factor to transaction throughput that simulates future application usage.

The standard of practice is to first migrate non-production or low-risk databases to the cloud. Thus, this comparison is valuable in case the company eventually decides to migrate production databases as well.

6. Post-migration performance monitoring with Foglith SQL-PI

Some difference in performance is to be expected between the on-premises Oracle DB and the Oracle instance in the cloud due to factors like network latency. Now that SharePlex is replicating to the cloud, use Foglight SQL-PI to continuously monitor database performance. Should any potential problems arise with cost, performance or future scalability, you can spot them in real time.


Using database management solutions from Quest, you can perform an Oracle migration to a public or hybrid cloud based on a service such as Amazon Web Services, Microsoft Azure and Oracle Cloud Infrastructure. You can then continue monitoring and administering your cloud databases together with your on-premises Oracle databases all from a single platform. Our solutions help you to determine the correct resource sizing now and in the future to ensure the right balance between application performance and cost.

With Quest tools, you can mitigate the risk of migrating Oracle databases to the cloud. You can optimize your service tier and licensing costs and confidently scale cloud resources and performance for future demand.