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Considerations when moving to S/4HANA – Defining the approach

Defining the overall approach for your company

 

Prior to my current role as Chief Strategy Officer at an SAP DevOps & Testing focused organization, I was leading the S/4 Transformation planning for Procter & Gamble. In this post, I want to share some of the key considerations when thinking about the move to S/4HANA for your organization. The following elements will be covered in a three part series of blog posts:

  • Part 1 – Defining the overall approach for your company

  • Part 2 – Avoiding Moratorium / Change Freeze

  • Part 3 – Handling custom code and managing a more complex, higher volume future S/4 landscape

 

In this first part, I will look at what approaches exist and the key factors that may influence which one is right for you.

The industry is generally using the following terms to describe the various options of how to move to S/4HANA from ECC:

move from s4hana to ecc table
Do not be afraid of SAP S/4HANA – a small guide for a safe change | blog.sap.com

 

Greenfield can be thought of like the initial implementation of SAP. Start out with “Mapping & Matching” comparing SAP Best practice processes to how you do things today, retrain end users on the new processes and migrate from your existing ECC systems to S/4 in waves or as a big-bang by migrating open items and master data across to the newly designed system.

Brownfield can be thought of like a more traditional upgrade, although SAP refers to it as a system conversion. Whilst >90% of the codebase is the same, it is considered a conversion as there are significant underlying changes in the data model (new GL, Business Partner, etc) and the new system MUST run on a HANA database. In certain cases, a system conversion will not be an option if certain Industry Solutions or Add-ons have been installed or certain Business Functions have been activated. It is worth understanding this very early in your planning process – ideally by running the S/4 Readiness Check. This readiness check will also highlight “Simplification Items” which are areas of the system which have a change to be reviewed / adjusted.

In between the two extremes is an additional flavor, also known as Hybrid / Bluefield / Blackfield which typically involves a degree of landscape transformation. Two basic Hybrid options exist, which we might call ‘Shell Creation’ and ‘Mix & Match’. In the former, a new ‘shell’ system is created in parallel to your existing landscape. This is based on a copy of an existing system (either Production or Development). All customization is retained, and S/4HANA related adjustments are made. Alternatively, in a Mix & Match approach, a new Greenfield-like S/4HANA system is created and a selected amount of legacy custom development (normally <30%) is carried over. The closer you are to the brownfield end of the continuum, the easier it is to extract, transform and load historical data as part of the migration. Companies which are leading the way on these types of migrations are SAP (DMLT), Datavard and SNP.

 

To highlight the key differences between the alternatives, I have put together the following table:

s4hana alternatives table

There are some key considerations which could determine which of these approaches is best for your company. The table below shows some examples, and how the three migration options stack up in each case. However, it is worth noting that there may not be a “one-size-fits-all” for your transformation. Some landscapes could warrant Greenfield (e.g. S/4 Central Finance), whilst others could justify Brownfield or Hybrid.

s4hana project comparison table

Whilst not in the same format as the above table, SAP has similar guidance when selecting between the more binary choice of Greenfield and Brownfield.

comparing path to s4hana table
The right approach to S/4HANA Blog Post #9: The epic battle Greenfield versus Brownfield | blogs.sap.com

In summary, whichever route you select, it is important to understand how long you will be in a transition period from start to finish and what events you need to plan for during that time (things like in-flight upgrades of your new S/4 landscapes, for example). In the next blog I will share details of managing change during this transition period and how to avoid a moratorium / change freeze.

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