My review of the some of the important note that i took when performing S/4hana migration, below is just brief but there are more to it which you should refer to the SAP guide.
What is SAP's 4HANA migration cockpit, and how does it work?
The SAP S/4HANA migration cockpit makes it easier to move corporate data from one system to another. Migration objects are used by the SAP S/4HANA migration cockpit to identify and transmit important data. A migration object explains how to transfer data from SAP S/4HANA to a specified business object.
The SAP S/4HANA Migration Cockpit aids in the data migration process from SAP/non-SAP systems to SAP S/4HANA using preset migration objects. The source and target structures, as well as relationships and mapping information, are all detailed in the migration object.
SAP Migration Cockpit (SMC) is a new tool from SAP that is integrated into both cloud and on-premises versions of SAP S/4 HANA. It's designed to help with data transformation and loading into SAP S/4 HANA.
The process of shifting data from one system to another is known as data migration. While this may appear to be a simple task, it necessitates a change in storage as well as a database or application. Any data migration will include at least the transform and load steps in the extract/transform/load (ETL) process.
How long does it take to migrate SAP?
depends roughly 10 to 15 months or more depending on type and size
Moving from traditional SAP systems to SAP S/4HANA should take between 10 and 15 months, according to SAP.