As mentioned in the previous lesson, a customer has two important decisions to make in their journey towards SAP S/4HANA, as follows:
- Which SAP S/4HANA deployment option to use:
- SAP S/4HANA Cloud, public edition
- SAP S/4HANA Cloud, private edition
- SAP S/4HANA
- Whether to deploy using a system conversion (also known as Brownfield), a new implementation (also known as Greenfield), or a landscape transformation approach (also known as Selective Data Transition).
If the customer decides to convert their existing SAP ECC system then they can choose either SAP S/4HANA Cloud, private edition or (if they wish to keep their ERP landscape on-premise) SAP S/4HANA. The same applies for a landscape transformation approach. There is no system conversion or landscape transformation option for SAP S/4HANA Cloud, public edition; a new implementation is the only choice. Customers may also elect to pursue a new implementation approach for SAP S/4HANA Cloud, private edition or SAP S/4HANA if desired. All options are compatible with a clean core approach, but may affect the expression of its execution and facets.
System Conversion (Brownfield Approach)
With a system conversion, a customer's private edition or on-premise system starts off as close as possible in important respects to their existing SAP ERP system. Effectively, a customer builds their new SAP ERP system using their existing one as a template. After the conversion is done, the necessary rework based on the project scope can begin. With a system conversion, the goal is to get the core clean.
New Implementation (Greenfield Approach)
With a new implementation the target (public edition, private edition, on-premise) by definition inherits no legacy custom code from the legacy SAP ERP system. The project team does not need to worry about modifications to revert or extensions to adapt. In addition, the system starts of with a clean core by default. This does not mean that new extensions based on the SAP S/4HANA Cloud extensibility model (to be discussed in a later lesson) won't be needed, but the migration project is simpler in some ways, due to the elimination of conversion work. Also, instead of a "big bang" approach to rolling out the new system, a phased rollout can be done (based on company code, for example). With a new implementation, the system starts off clean by default. So, the goal is to keep the core clean.
For customers with a large number of disparate ERP systems (for example, due to a history of frequent mergers and acquisitions), a selective data transition allows them to consolidate configuration and data from multiple ERP systems to either a private edition or on-premise system.