Guideline Implementing Failover through Load Balancing within IBM Cognos 8 Product(s): IBM Cognos 8 Area of Interest: Infrastructure
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3 Contents INTRODUCTION...4 PURPOSE...4 APPLICABILITY...4 ASSUMPTIONS AND EXCLUSIONS...4 THE IBM COGNOS 8 APPLICATION TIER... 5 CONFIGURATIONS...5 IMPLEMENTING IMPLEMENTING THE THE FAILOVER CONFIGURATION...6 LOAD BALANCE CONFIGURATION...9 TESTING THE FAILOVER... 10 ABOUT THE AUTHOR(S)...11
4 1 Introduction 1.1 Purpose This paper talks about the implementation of failover through load balancing within the IBM Cognos 8 Application tier. 1.2 Applicability The steps outlined in this document were validated using: One server with a full base install of IBM Cognos 8 including gateway, dispatcher, content manager and content store. One server with only the dispatcher installed. 1.3 Assumptions and Exclusions This document assumes that the reader has a basic understanding of the IBM Cognos 8 installation and configuration. This document also assumes that: Only one IBM Cognos 8 instance is running on each server.
5 2 The IBM Cognos 8 Application Tier The Application tier of IBM Cognos 8 is where the majority of the processing is performed. Components of the Application Tier receive user requests from the Web Tier components or directly through rich clients and must fulfil them appropriately. In turn, the Application Tier will often have to query the data and process the results and send them back to the presentation layer. Due to this it may be necessary to provide failover and load balancing to the application tier through the addition of another IBM Cognos 8 dispatcher which shares a common IBM Cognos 8 gateway and IBM Cognos 8 content manager. The following sections will provide the detailed implementation steps required to perform this task. 3 Configurations For the purpose of this document an IBM Cognos 8 full base installation is installed on Machine 1. This machine will be named ajay_j. The machine with only the dispatcher is installed; Machine 2; will be named s_singh. This is illustrated in the figure below.
The installation options can be picked up for both the machines as: Machine 1 (ajay_j) Machine 2 (s_singh) 3.1 Implementing the Failover Configuration 1. Open IBM Cognos configuration window of full base installation (ajay_j). 2. Go to Environment Gateway Settings Dispatcher URIs for gateway. 3. Include dispatcher URI of dispatcher only IBM Cognos installation (s_singh). Once complete the configuration should represent the following screen capture. 6
7 4. Click OK to return to the main configuration. 5. Click on Save Configuration and then click on Restart to restart the service as shown below. 6. Open Cognos configuration window of only dispatcher IBM Cognos 8 installation (s_singh) 7. Modify values of Gateway URI and Content Manager URIs to reflect values pertaining to full base IBM Cognos Installation. This is illustrated by the following image.
8 8. In the same window, delete the original content store connection and create a new content store connection which points to the content store of full base installation (ajay_j). 9. Give an appropriate name to the connection. 10. Right click on the connection and click on Test, to test the connection to content store. 11. Save the configuration and restart the service as illustrated earlier. 12. Using a browser, log in to IBM Cognos Connection using the gateway URL as an administrator and go to Launch IBM Cognos Administration System. 13. Check that both the systems are now registered and marked as Available as shown in the following image. This completes the failover configuration of two dispatchers.
3.2 9 Implementing the Load Balance Configuration Load balancing, using IBM Cognos 8 capability, is achieved using a weighted round-robin algorithm. An administrator can assign a weight to each dispatcher. The higher the weight of a dispatcher the more it will be favoured during the work assignment. In IBM Cognos 8, you can set process capacity settings using the following steps. 1. Click on the dispatcher which needs to be configured for load balancing, click on Set Properties. 2. Then click on Settings. Under Category tab, then click on Tuning. 3. Set an appropriate value for processing capacity based on the load balancing requirements. 4. Click on OK. 5. Follow this step for both the IBM Cognos 8 installations as shown below.
10 4 Testing the Failover Once the configuration is complete, it is advisable to test whether it is working as expected. This can be done by alternately stopping the individual dispatchers and running a report. A report executed within a new session should be unaffected by stopping of a single dispatcher. The image below illustrates the stopping of a dispatcher within IBM Cognos Administration.
4.1 11 About the Author(s) Ajay S Joshi works for IBM Cognos on system Z team out of IBM - India Software Lab, Pune. He has extensive experience in back end testing of UNIX based business applications. During his free time, he likes playing chess. Sachchidanand Singh works with the IBM Cognos on system Z team and works out of IBM - India Software Lab, Pune. He has been involved in the analysis, design, enhancement, maintenance and testing of business application software s involving Mainframe, UNIX, BI & Data Warehouse technologies. During his free time, he enjoys watching cricket.