The Oracle Cloud computing platform is an excellent target environment for transitioning from a mainframe workload to a cloud implementation. With the security features of Oracle Cloud and the ability to scale based on demand for the services, Oracle Cloud offers a complete operational environment in support of mainframe workloads that have been migrated to the cloud. In addition, Oracle Cloud supports new innovation of the application portfolio, previously held captive by the inflexible nature of a mainframe computing model, improving the productivity of application developers and support personnel.
Begin by reading the “Why Should I Migrate” section first. From there:
Mainframe Experts: Skip to the Unisys to Oracle Cloud Reference Architecture and the Understanding Oracle Cloud sections
Oracle Cloud Experts: Start with the Understanding Unisys section, followed by the Reference Architecture.
Business Leaders: Spend time with the “Why Should I Migrate…” section and the Ensuring Project Success section at the end.
Over the past 10 years, public cloud computing has emerged as the foundation of future enterprise technology. In terms of technology generations, mainframes are at least two generations old, perhaps three. Yet, they still survive today and are responsible for running key financial, healthcare and other vital and sensitive systems around the world.
So, why should you migrate your mainframe workloads, why migrate them to Oracle Cloud and why is now the right time?
You may notice throughout this document that we use the terms “Mainframe Modernization” and “Mainframe Migration”. Migration is a type of modernization, whereas modernization encompasses a broader set of strategies or options. In many cases, you will employ a combination of these strategies, the right mix of which ones will be determined during the critical application portfolio rationalization step of the project’s assessment phase. Here are three of the most common approaches:
Reuse – Often called “lift and shift”, this is a process that reuses the existing code/program/applications, typically written in COBOL, by moving them off the mainframe, and recompiling the code to run in a mainframe emulator hosted in a cloud instance. This approach minimizes the upfront risks and the length of the project, realizing hardware and software cost savings soonest.
Running mainframe applications in an Oracle Cloud-hosted emulator also opens the possibility of new innovation leveraging APIs to previously inaccessible programs and data.
Rewrite – It may be tempting to say, “Let’s just write new programs from scratch,” to modernize the mainframe applications. This approach is extremely risky and fails a vast majority of the time. It is complex, costly, and time consuming. The resources and investment required tends to greatly exceed the forecast.
A new, modern codebase may still be the correct end objective, but a better approach would be to first move the applications to a cloud-based emulator, migrate the database to a cloud-based database, then focus on replacing modules/code over a deliberate, multi-phased approach. When it is time to rewrite, there are several code transformation engines you can choose from to reduce the effort and minimize the risk.
Replace – Another mainframe modernization approach is to completely replace the mainframe functionality with a program or suite of programs, typically a Software-as-a-Service (SaaS) application. You typically see this with purpose-built solutions for finance, human resources, manufacturing, enterprise resource planning, etc. There are also industry specific apps that may solve the problem that a custom mainframe solution was needed for decades ago.
The upside of using SaaS is that your organization no longer worries about maintaining code. However, you will find that while you can configure a SaaS application with various options provided by the vendor, you will not be able to customize your instance, as the shared codebase runs all tenants (customers/organizations) using the “service”.
There are additional variations on these three modernization approaches and you’ll likely use several strategies in achieving your goal to completely migrate from the mainframe. It is commonly accepted best practice among legacy modernization practitioners to primarily use the lower-risk, lower-cost Reuse approach first to capture the gains and benefits in the shortest time possible, followed by a deliberate and phased approach to Rewrite or Replace the applications.