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The seven Rs of cloud migration: Part Three

Explore the pros, cons, and best practices of seven cloud migration options. Here: Retain, Repurchase, and Retire

November 08 2021Nico Herzhauser

Cloud migration: To move or not to move?

In part one, we looked at the lift and shift method - Re-host, and its equivalent if you run your on-premises IT on VMware – Re-locate. In part two, we reviewed Re-platforming and Re-factoring. But sometimes, there are good reasons not to migrate an application. As part of your cloud strategy, these two no-migration options - Retain, and Retire – may be helpful to consider. Or you could buy an alternative SaaS solution and Repurchase.

Why retain your application?

server room with a cloud

Retain means doing nothing for now and revisiting later. Some organizations keep elements of their IT portfolio because they are not ready to migrate or feel more comfortable keeping specific applications on-premises. And there may be pragmatic reasons for them to retain an application on-premises or in a data center. For example:

  • Their workload is in an area with poor connectivity to the cloud 
  • They have specialist software with no current cloud equivalent 
  • They recently upgraded the application and don't want to change it again 
  • They may not require their application or system for much longer, so there is no sense in migrating it 

You should only migrate what makes sense for your business, but the more your portfolio moves to the cloud, the fewer reasons you will have to retain.  

The pros and cons of retaining your app 


  • As you work towards a cloud-first strategy, a phased transition minimizes disruption for your application’s users and avoids overstretching your IT resources


  • Operationally, a hybrid environment is more complex to manage and may not give you complete visibility of your IT estate 
  • The potential for silos, which could pose challenges around data integration, reporting, and analytics 
  • The experience of your user base, who may have to use multiple logins as they work across your cloud and legacy environments 
  • Retaining your application means that it will take longer for you to realize the benefits of the cloud, such as a simpler operating model and improved cybersecurity.  

But none of the challenges of managing a hybrid environment are insurmountable, and you can have the best of all worlds; an expert partner can help you build your strategic roadmap to the cloud. 

Why Repurchase your application? 

Casually referred to as ‘drop and shop’, Repurchasing replaces your on-premises software with SaaS (Software as a Service). SaaS vendors deliver applications over the internet, typically on a subscription basis. And for some organizations, an OPEX model is preferable to CAPEX because it helps them better predict and manage their costs.   

The decision to move to a newer version or a different solution likely means your organization is willing to change your existing licensing model. For workloads that can be easily upgraded to the latest versions, this strategy might allow a feature set upgrade and smoother implementation. The SaaS option is ideal for everyday business functions with no market advantage, like HR or CRM systems. SaaS vendors often offer a direct cloud-based replacement for on-premises systems, and the necessary training for users is minimal.

The pros of Repurchasing your app

Cloud Structure
  • Replacing your legacy apps with SaaS avoids the risk and burden involved in migration
  • SaaS advantages include lower upfront costs, rapid configuration, scalability, and ease of use 
  • SaaS vendors pump vast sums into regular improvements 
  • You have the luxury of shopping around to find the service that best fits your organization’s needs.
  • If you see something better in the future, switching to another app is relatively straightforward
  • Unlike your legacy apps, you need not concern yourself with compatibility. Because SaaS applications are cloud-native, they are built to leverage the benefits of a cloud environment, such as security and ease of integration with other services
  • Because the cloud provider hosts the application, upgrades, maintenance, and security patches aren’t your responsibility any longer and happen automatically   
  • SaaS also offers an easy entry to the latest technologies, such as AI

 The cons of Repurchasing your app 

What about the potential downsides of replacing your legacy application? It’s highly likely the advantages will outweigh them, but it is worth being mindful of:

  • Employee engagement. Your users may be emotionally attached to your legacy application and resistant to change. They could be apprehensive at the prospect of something new and different. You can help your replacement application to stick by collaborating with your users base early and, where possible, involving them in the decision-making process.     
  • Loss of future ROI. There may be life in your custom-built app, and the return on your investment will cease. However, the cloud can offset this through cost advantages and efficiency savings.   
  • Autonomy – you will have limited say in the SaaS application’s future features and may not always like the changes the vendor implements. However, in a competitive market, you could always choose another SaaS app. 

Why Retire your application?  

As you consolidate your applications and workloads during your exploration phase, you may find that some are no longer necessary, and you can decommission or archive them. Perhaps they have become defunct because of modern ways of working and are no longer fully utilized. Or you could justify their retirement because of the new functionality offered by your other applications or replace them with simpler and more efficient cloud apps. 
Identifying IT assets that are no longer useful and can be switched off can help boost your business case as it concentrates the precious resources of your IT team on maintaining assets that are widely used.  

About the author

Nico Herzhauser

Solutions Architect, T-Systems International GmbH

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