Book Image

Modernizing Legacy Applications to Microsoft Azure

By : Steve Read, Larry Mead
Book Image

Modernizing Legacy Applications to Microsoft Azure

By: Steve Read, Larry Mead

Overview of this book

Organizations have varying circumstances, objectives, and prerequisites when contemplating a hyper-scale cloud solution transformation to a platform such as Azure. Modernizing Legacy Applications to Microsoft Azure uncovers potential scenarios and provides choices, methodologies, techniques, and prospective possibilities for transitioning from legacy applications to the Microsoft Azure environment. You’ll start by understanding the legacy systems and the main concerns regarding migration. Then, you’ll investigate why distributed architectures are compelling and the various components of the Azure platform needed during migration. After that, you’ll explore the approaches to modernizing legacy applications and the Rs of modernizing (i.e., rehost, refactor, rearchitect, and retire). You’ll also learn about integration approaches and potential pitfalls. By the end of this book, you’ll be well equipped to modernize your legacy workloads while being aware of pitfalls and best practices.
Table of Contents (18 chapters)
1
Part 1: Legacy Estate Options
3
Chapter 2: Strategies for Modernizing IBM and Unisys Mainframes
6
Part 2: Architecture Options
10
Part 3: Azure Deployment and Future Considerations

What is mission-critical?

We will start with some semantics here, starting with what it means to be mission-critical and the ways to achieve this in modern Information Technology (IT) architectures. If you look up the definition of mission-critical, you will find that it means something vital to the function of an organization. In the case of software systems, we can probably all agree on what those types of systems are and why they need to be running as close as possible to 100% most of the time. If we peel the onion on this a little bit, we will discover that there are different levels of mission-critical. They are typically defined by two key metrics:

  • Recovery Time Objective (RTO): Simply stated, the RTO is the amount of time that the mission-critical system can be allowed to be out of service. This implies that after a certain point in time, there will be severe business implications if the system is not performing. As we will see, there are different approaches for different...