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Setting Load Balancing for Loading Processes to the BW SystemLocate this document in the navigation structure

Use

There are various scenarios for load balancing of loading processes from a source system to the BW system:

  • Scenario 1: A single host or instance for loading processes

    Your want to define one instance for data loading processes, while the other instances are to be used for other BW activities, such as reporting and analysis. This could be because your organisation has to perform loading processes and reporting and analysis all at the same time. As part of your performance tuning strategy, you want to ensure that your hardware resources are fully exploited in order to balance the load arising from these crtitical activities over various hosts, thus ensuring that all hosts can be optimized for the processes running on them. Another reason for defining a host as the host for loading processes could be if you want to minimize the network traffic by running loading processes on the database host. If new data was written to the database during the loading process, there would be no additional network traffic.

  • Scenario 2: Multiple hosts or instances for loading processes

    You want to balance the load over multiple hosts or instances in order to optimize processing of loading processes. This scenario describes the system behaviour for loading processes that are mainly processed in dialog work processes. This is normally the case for SAPI extraction from SAP source systems with tRFC. If you load a 3.x InfoPackage with the setting Load PSA and then to Data Targets, the statements below apply only for the first part of the loading process, to the PSA. The data is loaded to the InfoProviders in the background.

    • Scenario 2.1: Multiple source systems

      A simple but inflexible approach for load balancing can be used in a scenario where multiple SAP source systems feed a single BW system. You can specify a different BW host (and instance) in each source system.

    • Scenario 2.2: Regardless of the number of source systems

      This approach uses a logon group to balance the load equally over all instances in the logon group. You can either create a logon group or use an existing one and adapt it as necessary. Whether you can use this function depends on the release of the source system. For more information, see SAP Note 593058.

Procedure

Scenario 1: A single host or instance for loading processes

  1. Call the configuration of RFC connections in the source system. To do this, choose Start of the navigation path Tools Next navigation step Administration Next navigation step Administration Next navigation step Network Next navigation step RFC Destinations End of the navigation path (transaction SM59) in the source system.

  2. Search for the connection used for data transfer to the BW system.

    The usual naming convention for connections of this type is <system ID>CLNT<client number>, for example AB5CLNT003. Note that connections with naming convention <system ID>CLNT<client number>_DIALOG are not normally the ones that are required here. Take into account previous configurations that have been made for this connection.

  3. To call the destination maintenance transaction, double-click the connection.

  4. On the Technical Settings tab in group frame Target System Settings, set the radio button for Load Balancing to No.

  5. Enter the target host here, together with the relevant system number for the instance being used.

Scenario 2.1: Multiple hosts or instances for loading processes: Multiple source systems

Specify a different target host (and instance) in each source system for the connection to the BW system. In each source system, proceed as described in scenario 1.

Scenario 2.2: Multiple hosts or instances for loading processes: Regardless of the number of source systems

  1. Create a logon group in the BW system, then assign instances to it and activate dynamic RFC load balancing. To do this, choose Start of the navigation path Tools Next navigation step CCMS Next navigation step Configuration Next navigation step Logon Groups End of the navigation path (transaction SMLG).

    If a suitable logon group already exists, you can adapt this logon group using the steps listed below.

    1. To create a logon group, call the CCMS: Logon Group Maintenance screen and press the Create Assignment button.

    2. In the dialog box that appears, choose the Assignment tab and enter a name for the logon group.

    3. Specify the instance that you want to add to the logon group.

    4. Activate dynamic RFC load balancing for the logon group. To do this, choose the Assignment tab and the Group Specific group frame and select the Allow External RFC field.

    5. Press the Apply button.

    6. To add more instances to the logon group, call the CCMS: Logon Group Maintenance screen and press the Create Assignment button again.

    7. In the dialog box that appears, select the logon group you created before and specify the next instance that you want to add to the logon group.

    8. Press the Apply button.

    9. Repeat steps 7 to 9 for all instances that you want to add to the logon group.

    10. Save your settings on the CCSM: Logon Group Maintenance screen.

      In the logon group maintenance transaction, the system now displays every instance that you have assigned to the logon group.

  2. Adjust the parameter for dynamic RFC load balancing in the BW system.

    1. Call the Data Browser (transaction SE16).

    2. Enter the table name RZLLICLASS and choose Table Content.

    3. To display all entries from the table, choose Execute on the next screen.

    4. On the next screen, select the entry for your logon gorup and choose Change.

    5. Change the value in the FAVTYPE field (Logon group: Method for determining preferred server) to R and save your change.

      R stands for round robin. This means that the next server in the list will be used for the next logon.

  3. Adjust the RFC connection in the source system.

    1. Call the configuration of RFC connections in the source system. To do this, choose Start of the navigation path Tools Next navigation step Administration Next navigation step Administration Next navigation step Network Next navigation step RFC Destinations End of the navigation path (transaction SM59) in the source system.

    2. Search for the connection used for data transfer to the BW system.

    3. To call the destination maintenance transaction, double-click the connection.

    4. On the Technical Settings tab in group frame Target System Settings, set the radio button for Load Balancing to Yes.

    5. In the fields that appear now, enter the name of the target system, the message server for the target system and the logon group that you have created, and save your entries.

When you load data, the global work process overview (transaction SM66) will now show how the tasks are balanced over the instances defined in the logon group for the loading processes.