Consistent Delta Migration System
The tool ‘Consistent Delta Migration System’ (CDMS) will focus on making the SAP ERP Quality system (created using Test Data Migration system (TDMS)) consistent.
SAP Test Data Migration Server (SAP TDMS) is used for creating and refreshing non-production systems (particularly test systems) with a reduced dataset.
Some of the key features of SAP TDMS are:
- TDMS replaces full copies
When you replace numerous full copies of productive clients by reduced clients created by TDMS, this significantly saves disk space and administrative costs (which are in proportion to your system size). Yet, you will have additional effort and costs caused by
- The TDMS implementation
- The TDMS execution (for an experienced user, the effort will be slightly higher than the effort for a system copy)
- The reduced set of transferred data, which might lead to some additional test effort at the beginning of the project
When you create new clients with production-like data, the benefit will be an improved quality of test data because target-oriented and reduced test data will be provided. This will lead to cost savings due to more efficient and quicker tests as well as a better quality of developments.
As mentioned, the common method of test system creation is to install a copy of the production system on the test machine – and besides the huge hardware requirements, a lot of manual work needs to be done until the system can be made available for the users
Some of the manual work that would be required:
- Interfaces (change/shut down)
- Create new users or block existing ones
- Assign new authorizations
- Copy saved objects back into the system (CATTS)
- Logical System Change (BDLS)
TDMS helps in avoiding all the manual work and almost all the post processing activity are minimized.
SAP TDMS operates at client level, that is, the selected data from a client in the sender system is copied to a client in an existing system (non-production system).
TDMS can be used in a variety of situations. For example you can:
- Create a separate client for testing purposes within the development system and supply it with current data from the production system
- Supply clients in quality assurance, testing and training systems with current data
- Build up a system with a reduced data set for testing upgrades
- Create multiple clients with different data sets in development and use these clients as master clients to supply clients in other testing or training systems with data after a system reset
TDMS System Landscape
The system infrastructure for a data transfer using SAP TDMS requires the following system roles:
- A sender system (client) from which the data supply for the non-production system is taken. Usually the production system is used as the sender system. However there are other options as well. For more details, see the solution operation guide.
- The TDMS server, which includes:
- A central system (client) on which the settings and customizing for the setup of the non-production system are stored
- A control system (client) from which almost all activities for SAP TDMS are triggered and monitored
- A receiver system (client) (the non-production system to be filled)
As mentioned TDMS transfers data from all the modules of SAP to the quality system, therefore the quality system is approximately 90-95% consistent.
Reasons for inconsistency:
- As SAP is a highly customizable product all the customers have configured there systems as per their own requirements. For e.g. The HR module of a company ABC is customized such that all the leave approval will first be directed to the HR manager of the company rather than the reporting manager. The change in the standard procedure might also lead to change of references within the tables which cause inconsistencies. TDMS is a standard tool and the transfer of data takes place based on the standard settings.
- While TDMS was in progress, some temporary issue occurred and data from few of the tables were not transferred from the production to the target system. At times, the control table of TDMS also fails to update the information of such tables. In such cases, the user has no way to determine the erroneous tables. Hit and trial will only be the possible way to find out the names of the table with error.
In either of the two mentioned cases, ‘Consistent Delta migration system’ will transfer the delta from the production system to make the TDMS created system as consistent.
The below mentioned figure explains the normal processing of data migration using TDMS.
Flow of CDMS:
Unlike TDMS, the re-transfer will be initiated from the receiver system.