Legacy Architecture Migration Patterns
10:40 - 11:10, 27th of May (Tuesday) 2025 / DEV ARCHITECTURE STAGE
We all struggle with legacy code and want to modernize our old systems. But the journey from the architecture we have now to the shiny new modernized system we want to have can be long.
Along the journey we have to choose patterns for migrating from the current to the new architecture. Most likely we will have new and old running in parallel for many months or multiple years. That means we need to keep multiple systems and datastores in sync. To do so, there are many patterns we can choose from and many risks and trade-offs we need to consider.
You've probably heard of the strangler fig pattern, but the topic is far deeper and more nuanced than that. For example: you could have all write operations going to the legacy and all read operations to the new system or vice-versa? Or you could allow write operations in both and have bi-directional synchronisation. And there are many variations and shades of grey.
The patterns you choose will have a tangible impact on your modernization journey. In this talk Nick will share real examples he has encountered over the past 15 years, including recent examples from his time at PayFit, so you can better decide which patterns are optimal in your context.
