Technology Record - Issue 35: Winter 2024

68 VIEWPOINT The convergence of mainframes and cloud computing is reshaping how modern enterprises do business, but which migration method is the right one? KEN GAMBON: KYNDRYL Kyndryl’s 2024 State of Mainframe Modernization Report found that 96 per cent of organisations are moving, on average, at least 36 per cent of their workloads to the cloud. A hybrid approach allows organisations to take advantage of the performance and security of mainframes while enjoying the flexibility offered by the cloud. However, modernising or moving mission-critical workloads to a cloud platform can be challenging as these have strict performance and security requirements. Even if you plan to move an entire mainframe to the cloud, the migration will likely be done in stages. Since workloads and data will be in a hybrid environment during this process, firms need to take extra steps to help ensure ongoing access to data, security and fast connectivity. One of the key decisions developers will have to make when migrating is whether to refactor, replace or replatform applications. Refactoring app code is like renovating a kitchen. However, instead of changing out obsolete fixtures, restructuring existing code optimises app performance. This approach makes sense when an app’s original code is generally well written but needs to be updated to a newer programming language. For example, converting COBOL to .NET or Java. Although the refactored app functions much like the original, the updated code should improve overall efficiency, quality and maintenance. Refactoring can take longer than other migration approaches because IT teams need to fully understand the original code and business logic before converting it. However, refactored apps are often easier to maintain because there are more developers available with skills in modern languages to update the software. Our team is refining commercial processes to refactor apps at scale on Microsoft Azure. We use a portfolio analyser tool to identify data dependencies on the overall mainframe landscape before converting the original code. To help detect and reduce errors, we also run apps on both the mainframe and the cloud throughout the migration phase. Once converted to the new language, refactored apps function like .NET containers running on Azure. This approach enables software enhancements while keeping the existing business logic intact. Out with the old and in with the new is the premise behind the replacement approach. It entails completely discarding old apps and starting from scratch with software-as-a-service or off-the-shelf products. Replacing apps may be viable when older technology can no longer meet business needs or has become too complex to support. This method eliminates the need to rework existing software and maintain custom code, making “ The overarching goal should be to put the right workload on the right platform” Refactor, replace or replatform

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