Emulation, Migration and Restoring
DataSources 
Emulation
A DataSource 3.x (R3TR ISFS) exists in the BI database in the metadata tables that are valid for releases prior to SAP NetWeaver 2004s.
During emulation (displaying and using DataSource 3.x with the interfaces of the new DataSource concept), the DataSource (R3TR RSDS) is instantiated from the metadata tables of the earlier releases (R3TR ISFS).
You can display a DataSource 3.x as an emulated DataSource in DataSource maintenance in BI. You can also model the data flow with transformations for an emulated DataSource if there are already active transfer rules and a transfer structure and a PSA for the DataSource 3.x. Once you have set the data flow, you can set the processes for data transfer (load process using InfoPackage and data transfer process), along with other data processing processes in BI. We recommend that you use process chains.
Emulation and defining the data model and processes that are based on it in accordance with the new concept are a preparatory step in migrating the DataSource.
See also:
Migration
You can migrate a DataSource 3.x to a DataSource. If the DataSource 3.x already exists in a data flow for the old concept, you use emulation first to model the data flow with transformations and data transfer processes and then test it. Subsequently, you can deactivate the data flow you were using before and delete the metadata objects during migration.
We recommend that you use migration if you want to benefit from the advantages offered by transformations and data transfer processes; for example, if you want to perform real-time data acquisition.
When you migrate a DataSource 3.x (R3TR ISFS) in an original system, the system generates a DataSource (R3TR RSDS) with a transport connection. The DataSource 3.x is deleted, along with the 3.x metadata objects mapping (R3TR ISMP) and transfer structure (R3TR ISTS), which are dependent on it. If a PSA or InfoPackages (R3TR ISIP) already exist for the DataSource 3.x, they are transferred to the migrated DataSource, along with the requests that have already been loaded. After migration, only the information about how data is loaded into the PSA is used in the InfoPackage.
You have the option to export the 3.x objects, DataSource 3.x, mapping and transfer structure during the migration so that these objects can be restored. The collected and serialized objects are stored in a local table (RSDSEXPORT).
You can now transport the migration into the target system.
When you import the transport into the target system, in the after import, the system migrates the DataSource 3.x (R3TR ISFS) (as long as it is available in the target system) to a local DataSource (R3TR RSDS), without exporting the objects that are to be deleted. The DataSource 3.x, mapping (R3TR ISMP) and transfer structure (R3TR ISTS) objects are deleted and the related InfoPackages are migrated. The data in the DataSource (R3TR RSDS) is transferred to the PSA.
See also:
Restoring
If you exported and archived the 3.x metadata objects when you migrated the DataSource 3.x in the original system, you can make a new DataSource 3.x from the DataSource (R3TR RSDS). The system reproduces the DataSource 3.x (R3TR ISFS), mapping (R3TR ISMP), and transfer structure (R3TR ISTS) objects with their pre-migration status.
Only use this function if unexpected problems occur with the new data flow after migration and the problems can only be solved by restoring the data flow used previously.
When you restore, the DataSource 3.x (R3TR ISFS), mapping (R3TR ISMP) and transfer structure (R3TR ISTS) objects that were exported are generated with a transport connection in the original system. DataSource (R3TR RSDS) is deleted. The system tries to retain the PSA. This is only possible if a PSA existed for the DataSource 3.x before migration. This may not be the case if an active transfer structure did not exist for the DataSource 3.x or if the data for the DataSource was loaded using an IDoc. The InfoPackages (R3TR ISIP) for the DataSource are retained in the system. Available targets are displayed in the InfoPackages (this also applies to InfoPackages that were created after migration). However, in InfoPackage maintenance you have to reselect the targets into which you want to update data.
The transformation (R3TR TRFN) and data transfer process (R3TR DTPA) objects that are dependent on the DataSource (R3TR RSDS) are retained and can be deleted manually, as required. You can no longer use data transfer processes for direct access or real-time data acquisition.
You can now transport the restored DataSource 3.x and the dependent transfer structure and mapping objects into the target system.
When you transport the restored DataSource 3.x into the target system, the DataSource (R3TR RSDS) is deleted in the after image. The PSA and InfoPackages are retained. If a transfer structure (R3TR ISTS) is transported with the restore process, the system tries to transfer the PSA for this transfer structure. This is not possible if no transfer structure exists when you restore the DataSource 3.x or if IDoc is determined as the transfer method for the DataSource 3.x. The PSA is retained in the target system but is not assigned to a DataSource/DataSource 3.x or to a transfer structure.