Moving to the Cloud with SAP SuccessFactors: “Big Bang” vs. Phased Migration Approach

By on May 30th, 2020 in HCM Technology Solutions

Wondering how to most effectively move to the cloud? We put together a short guide to get you started. Continue reading or download the infographic.

As companies have begun transitioning to the cloud, we at GP Strategies have received a number of questions about the best way to transition from an on-premise SAP® system to cloud-based Employee Central (EC). Should you roll out EC all at once, “Big Bang,” or in a phased approach, by geography, business unit, etc.?

First you need to determine whether you plan on keeping your SAP system up to date after going live on EC or whether you will retire it. This will determine your approach.

In our experience, most companies choose to keep their SAP environment running on premise even after they begin moving to the cloud. That’s because most companies are running an existing payroll in SAP and aren’t yet ready to move to Employee Central Payroll.

Payroll is a complex process with a high number of existing integrations that need to be reproduced in Employee Central in order to make it work. This can be too daunting a task as part of the initial rollout because it requires coordination across many different vendors, all of which have their individual testing requirements.

In our opinion, the lower risk approach is typically to replicate from your Employee Central environment back to the legacy SAP platform and let the existing integrations and payroll processing run as they currently do.
However, each organization has its own goals and bandwidth considerations, so let’s review your two main options for migrating to the cloud.

The “Big Bang” Approach

If your plan consists of having all employees go live at the same time, you are looking at what’s called a “Core Hybrid” approach for your data replication back to SAP. This means that you will use Employee Central as your  system of record for all employees and the employee data will flow only one way (EC–> SAP).


1. Data migrations, conversion, data validation approaches, and all required regulatory approvals must be confirmed globally for go-live.

2. Switching to a phased approach after the project kick-off is NOT recommended because it requires a total redesign of your approach and replication process.

Begin your mapping process as early as possible!

The Phased Approach

If you plan on staggering your employee go-lives, then you are looking at a “Side-by-Side” or phased approach. This means that the live population will use Employee Central as the system of record and will replicate employees down to legacy SAP. For the non-live population, however, you will maintain SAP as the system of record and transfer the relevant information for these employees to Employee Central using either web service integration or file

1. Split your population by company or country for the phases.
2. Configure the allowed countries as part of the SAP inbound logic to filter out countries that are not in scope.

Filter the employees sent over by the inverse set of companies/countries as the live populations to avoid any circular employee updates.

We hope these pointers helped you understand whether an all-at-once or phased approach is right for you. If you have any questions, feel free to contact us.

Want more content like this? Subscribe to our blog to get it directly to your inbox!



Michael White

Leave a Reply

Your email address will not be published. Required fields are marked *


This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sort by Category

GPS Want to Learn More Widget

Want to Learn More?

GPS Connect With Us Widget