Use of Additional Hosts during Export
Why we need Additional Host? How does it help?
Especially for the migration to SAP HANA, it has become common to use an SAP HANA standby server for the import into the database instance. As SAP HANA servers are very powerful, the import is delayed because it has to wait for the relatively slow data delivery from the export. To increase the performance of the export you can use more than one SAP application server of the source system for the export. For example, you can use the hosts of the existing additional application server instances of the source system.
You can do this by choosing Database Instance Export on Additional Host in the SWPM installer.
With this option you can distribute the packages (to be exported) among the Central Instance and Dialog Instances of Source Host. An important Note that this option is only valid with Target DB as HANA.
Process Flow of Export:-
When performing the export you create a MIGRATION EXPORT image, which contains the data of the exported system, and which you use to install the target system.
The following figure shows the export options and the resulting output files.
Options To Be Selected On the HOSTS:-
The following options are selected on the Hosts and the screens that follow up after that need to be handled accordingly.
1) Running SWPM on Central Instance Host:-
Select Database Instance Export on Source System (Central Instance Host)
In the below mentioned screen Select “Use Additional Hosts”
In the next Screen Hostnames of Central Instances and Dialog Instances are mentioned. Make sure the Checkbox of “Use this Host” is marked for the Host on which SWPM is currently running.
The below screen mentions the Filename “package_filter_%hostname%.txt” which is generated by SWPM automatically (based on Size or Runtime) under the Export Installation Directory and Export Dump Directory (/<Export-DUMP>/ABAP/DB/HDB)
Once the below stage has been reached the Package Filter files are automatically created at the Export Installation Directory and Export Dump Directory by SWPM.
The following files are created in the Installation Directory and Export Dump Directory:-
- package_splitter_cmd.properties
- package_filter_visual_%hostname%:-Mentions the size of various packages/table/table_splits to be executed via a particular “hostname”.
- package_filter_%hostname%:- Mentions the name of packages/table/table_splits to be executed via a particular “hostname”.
- package_filter_files
Contents of package_filter_visual_%hostname%:-
Contents of package_filter_%hostname%
In case you want to change the list of Package Distribution to some Custom List then replace the package_filter_%hostname% file under
Export Installation and Export Dump Directory with your Custom List at the below mentioned stage:-
2) Running SWPM on Additional Host (Dialog Instance):-
Select Database Instance Export on Source System (Additional Host). Once the offloading of packages has started on the Central Instance Host SWPM has to be triggered on the Additional Hosts and the following Option is selected.
The Package Filter file for that particular Host is selected and SWPM is continued from there. The packages mentioned in the Package Filter file will occupy the resources only of that particular host.
