Migrating Oracle Databases to Database Cloud Service

Migrating Oracle Databases to Database Cloud Service

You can migrate your on-premises Oracle Database database to an Oracle Database Cloud database using a number of different methods that use several different tools.

Not all migration methods apply to all migration scenarios. Many of the migration methods apply only if specific characteristics of the source and destination databases match or are compatible. Moreover, additional factors can affect which method you choose for your migration from among the methods that are technically applicable to your migration scenario.

Some of the characteristics and factors to consider when choosing a migration method are:

  • On-premises database version
  • Oracle Database Cloud database version
  • On-premises host operating system and version
  • On-premises database character set
  • Quantity of data, including indexes
  • Data types used in the on-premises database
  • Storage for data staging
  • Acceptable length of system outage
  • Network bandwidth
  • To determine which migration methods are applicable to your migration scenario, gather the following information.
  • 1. Database version of your on-premises database:
    • Oracle Database 11g Release 2 version lower than 11.2.0.3
    • Oracle Database 11g Release 2 version 11.2.0.3 or higher
    • Oracle Database 12c Release 1 version lower than 12.1.0.2
    • Oracle Database 12c Release 1 version 12.1.0.2 or higher
  • 2. For on-premises Oracle Database 12c Release 1 databases, the architecture of the database:
    • Multitenant container database (CDB)
    • Non-CDB
  • 3. Endian format (byte ordering) of your on-premises database’s host platform
    • Some platforms are little endian and others are big endian. Query V$TRANSPORTABLE_PLATFORM to identify the endian format, and to determine whether cross-platform tablespace transport is supported.
    • Oracle Database Cloud uses the Linux platform, which is little endian.
  • 4. Database character set of your on-premises database and Oracle Database Cloud Service database
    • Some migration methods require that the source and target databases use compatible database character sets.
  • 5. Database version of the Oracle Database Cloud database you are migrating to
    • Oracle Database 11g Release 2
    • Oracle Database 12c Release 1

 

Oracle Database 12c Release 1 databases created on Oracle Database Cloud use CDB architecture. Databases created using the Enterprise Edition software edition are single-tenant, and databases created using the High Performance or Extreme Performance software editions are multitenant.
After gathering this information, one may see which migration methods apply to migration scenario.

Advantages of On-Premise:

Security

In my opinion, one can make the case that cloud security has surpassed the security measures at most private data centers. But certain companies are dealing with data that requires more advanced security than what cloud providers can offer. Or perhaps, the executives in the IT department simply feel more comfortable shouldering the risk themselves. In either case, security can be a legitimate determining factor in choosing to store data and apps on premises.

Regulations

Depending on your industry sector, vertical market, or geographical location, you may have to abide by an array of government regulations determining how you use and store sensitive data. The healthcare and financial services industries are common examples of verticals in which IT has to take extra steps to prove to the government that sensitive data is secure. And, in some cases, that means keeping sensitive data stored in private data centers.

Visibility

Do you really know where your data is? That’s one question that continues to haunt early adopters of public clouds. The fact is, once sensitive data is moved or generated on a public cloud, it becomes very difficult to see exactly where the data resides. Eventually, technology will overcome these cloud visibility hurdles. Until then, this is a very real concern for many of the IT professionals I speak with on a regular basis.

Accessibility

In a perfect world, all users in all locations around the globe will have high bandwidth and unfettered access into any of the various public cloud providers with which you choose to partner. We’re not quite there yet. The issue is especially problematic when you are operating a global company with remote sites in multiple countries. Access to cloud resources can become a problem due to bandwidth constraints at the last mile. Another factor to consider is situations in which certain countries restrict access to all sorts of Internet content. In such cases, accessibility using private WAN connections to private data centers can be more reliable and consistent compared to using public cloud offerings and relying on the Internet as your primary access method.

Latency

Latency within private data centers and across private WAN connections is easily controllable. On the other hand, when you are leveraging the Internet to access cloud resources, latency can become a major problem. If access to your data requires low and predictable latency times – as is the case with many audio and video data repositories — it’s usually much easier to manage and distribute this type of data when you control the network end-to-end.

Lack of Trust

Trust in a cloud provider is difficult to quantify. It depends on the specific needs of your enterprise, the cloud provider’s overall reputation, and the kinds of service-level agreements you have in place. Your organization’s level of trust with a specific cloud provider might transition multiple times throughout your relationship, depending on these and other factors.

When you’re considering the idea of housing sensitive data inside a public cloud, you should assume that, at some point, you will lose faith that your provider is keeping your data secure to the degree you have deemed appropriate. Trust issues are often the most difficult to overcome for IT executives when considering whether or not to move data and apps into the cloud.

Full control over the entire stack

Ability to performance tune hardware

Advantages of Cloud

Time-to-Market

As the pace of business rapidly increases, while at the same time internal IT resources remain in short supply at most companies, business managers are discovering an array of cloud solutions they can easily apply to their business operation without requiring the steps to acquire, install and maintain software. They can simply sign up for the solution and begin using it right away.

Economics

Cloud computing lowers technology costs in two ways. First by significantly reducing the need for IT experts and staff. The other is by efficiencies gained through shared multi-tenant cloud environments that eliminate purchasing hardware equipment and software licenses. Additionally, many services are month-to-month without long term contracts, allowing businesses to easily apply these technologies “just-in-time” and drop them when no longer needed.

Scalability

When a technology is custom-built or brought in-house, the IT managers must build an infrastructure that can withstand the highest point of usage or they risk their reputation not being able to deliver at peak times. In contrast, cloud services typically allow for on-demand scalability for peak times or sustained periods. IT no longer needs to over-engineer solutions and infrastructure or sacrifice quality of service.

Empowerment

Cloud solutions typically have a web-based interface for users. They can be accessed by employees, customers and partners no matter where they are. With a cloud computing database, everyone gets to work with the same set of information and spreadsheet chaos is a thing of a past.

Reduced Administrative Burden

A database with fewer features is less flexible — but it’s far more manageable. A cloud-hosted, mostly self-managed database doesn’t eliminate a database administrator, but it can eliminate unnecessary features that typically consume much of a DBA’s time and efforts. That allows a DBA to focus his or her time on more important issues. It can even allow a company to get started without a dedicated or full-time DBA, avoiding specialization that can cause team bottlenecks.

Best Practices

To the extent that reputable service providers are utilized, customers can be assured that best practices in terms of security, reliability, and monitoring are in place. The grade of service offered by leading cloud vendors is expensive and difficult to implement on your own.

Go Green

In addition to all of the business benefits, cloud computing is all about virtualization, multi-tenancy, and shared resources that provide more service for the amount of energy expended when compared to in-house, single tenant solutions.

Improved Security (in most cases)

If you’re running your databases on in-house servers, it’s your job to think seriously about security. You’ll need to ensure your database has an updated kernel and other critical software, and you’ll need to keep up with the newest digital threats. This is perfectly possible to do, but the reality is that most companies either don’t do it or do it poorly. Leave databases to the cloud company, and you’ll buy yourself some peace of mind.

Comparison of On-premise and Cloud

References:

  • 1. Table from GFI [https://www.gfi.com/whitepapers/Hybrid_Technology.pdf]
  • 2. Oracle Documentation [https://docs.oracle.com/cloud/latest/dbcs_dbaas/CSDBI/toc.htm]
  • Various blogs

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