Common Issues and Solutions in SAP ECC to S/4 HANA Migration

1. Direct External System Calls to SAP BAPI

In projects with tight development timelines, some interfaces are developed by external systems directly invoking SAP BAPI functions. This approach has the following advantages and disadvantages:

• Advantages: Eliminates the need for SAP to encapsulate BAPI functions, saving development time.
• Disadvantages: Complicates logging on the SAP side and introduces potential security risks.

To allow external systems to call SAP BAPI functions, configure the parameter ucon/rfc/check_blacklist = 0 in RZ10. For detailed steps, refer to SAP Note SAP Note 2295840.

2. Resolving ST22 DUMP Issues During Dialog Screen Rendering

When rendering Dialog screens, SAP’s security mechanisms may intercept certain remote function calls, leading to DUMP errors. To resolve this, add the following entries to the whitelist:

3. LTMC Batch Import Configurations

SAP’s LTMC tool facilitates batch data imports, reducing the need for custom batch import programs. However, LTMC has certain limitations:

• Enhancement fields cannot be imported for certain master data objects, such as material master data.
• For objects like equipment master data, enhancement fields can be imported by enhancing the BAPI in transaction LTMOM.

While LTMC offers stability due to server-side execution, it may be slower compared to custom-developed programs. For large-scale imports involving enhancement fields, consider using traditional batch import programs. Additionally, ensure that the LTMC service and application servers are properly configured, as they may not reside on the same server.

4. Addressing BP Creation Errors

During Business Partner (BP) creation, especially for vendor data, certain errors may occur. For instance, after creating the BP basic view using BAPI_BUPA_CREATE_FROM_DATA, it is necessary to extend the role using BAPI_BUPA_ROLE_ADD_2 and commit the transaction with BAPI_TRANSACTION_COMMIT before writing bank data. Failing to do so may result in DUMP errors.

Notably, in S/4 HANA 2021 versions, this sequence is mandatory, whereas in earlier versions, it might not have been required. Therefore, when performing BP-related batch imports in versions after 2021, ensure that the role extension and transaction commit are executed in the correct sequence to prevent errors.

5. Network and Interface Configuration Preparations

Before migrating to SAP S/4 HANA, ensure that internal network configurations are optimized to facilitate smooth system operations. Proper network setup is crucial for configuring interfaces and ensuring system stability post-migration.

Load Balancer Configuration

For direct interface connections, configuring a load balancer is essential. This setup allows for HTTP POST and Web Service interfaces to communicate effectively between SAP and external systems. To configure the load balancer:

• Contact SAP ECS (Enterprise Cloud Services) via email at sap.ecs.private.cloud.customer.center#sap.com to request the load balancer template and guidance based on your business requirements.
• Complete the provided template, which includes sections such as Internet Proxy (Outbound HTTPS) and Application Gateway (External). Ensure that all fields are accurately filled to reflect your system’s architecture and requirements.
• After completing the template, submit it to SAP ECS for processing. They will assist in configuring the load balancer to facilitate seamless communication between SAP and external systems.

Proper configuration of the load balancer ensures that interfaces function correctly, contributing to the overall stability and performance of the SAP system post-migration.