Overview Of IBM COGNOS BI

SOA platform architecture

IBM Cognos BI delivers a broad range of business intelligence capabilities on an open, enterprise-class platform. All capabilities—including viewing, creating and administering dashboards, reports, analysis, scorecards, and events—are accessed through web interfaces.

The IBM Cognos Platform delivers the qualifications to manage business intelligence functions with centralized, web-based administration that provides a complete view of system activity as well as system metrics and thresholds so that organizations can resolve potential issues before there is a business impact. The IBM Cognos Platform is built on a web-based service-oriented-architecture (SOA) that is designed for scalability, availability, and openness. This n-tiered architecture is consists of three server tiers:

• The web tier
• The application tier
• The data tier

These server tiers are based up on the business function and can be separated by network firewalls. Reliability and scalability were key deliberations when designing the IBM Cognos Platform. Services in the application tier operate on a peer-to-peer basis, which means that no service is more important and that there are loose service linkages. Any service of the same type, on any machine in an IBM Cognos Platform configuration, can satisfy an incoming request, which results in complete fault tolerance. The routing of requests is done in an optimal way, with automatic load complementary built into the system.

The IBM Cognos Platform provides optimized access to all data sources, including relational data sources and online analytical processing (OLAP), with a single query service. In addition, this query service understands and takes benefit of the data source strength by using a grouping of open standards such as SQL99, native SQL, and native MDX to optimize data retrieval for all these different data providers. The IBM Cognos BI user interfaces are accessed through the web tier.

 IBM Cognos Platform server roles 

To ensure optimal performance, IBM Cognos Platform services are normally grouped together to fulfil certain roles inside a distributed deployment for business intelligence applications. These server roles also classify the tier within the architecture that an IBM Cognos BI server uses.

Web tier: The IBM Cognos Gateway

The web tier provides user session connectivity to IBM Cognos BI applications. The IBM Cognos components that fulfil this role are referred to as the IBM Cognos Gateway. 

The IBM Cognos Gateway component manages all web communication for the IBM Cognos Platform. The workload on the IBM Cognos Gateway server requires minimal processing resources. For high availability or scalability Data Source OLAP IBM Cognos Content Store Security Namespace Security Namespace IBM Cognos Gateway Dispatcher IBM Cognos Report Server Dispatcher IBM Cognos Report Server Dispatcher IBM Cognos Content Manager Data Tier Firewall/Router/Encryption Application Tier Firewall/Router/Encryption Presentation/Web Tier 12 IBM Cognos Business Intelligence  , you can deploy multiple redundant gateways along with an external HTTP load-balancing router. 

Application tier: Server components 

The application tier for the IBM Cognos Platform is made up of three main server components:

• IBM Cognos Dispatcher 
• IBM Cognos Report Server
• IBM Cognos Content Manager

Application tier servers are tranquil of a collection of loosely-coupled Java™ and C++ services.

IBM Cognos Dispatcher 

IBM Cognos Dispatcher performs the load balancing of requests at the application tier. The IBM Cognos Dispatcher component is a lightweight Java servlet that manages (and provides communication between) application services. At startup, each IBM Cognos Dispatcher registers locally available services with the IBM Cognos Content Manager. During the normal operation of IBM Cognos BI services, requests are load balanced across all available services using a configurable, weighted round-robin algorithm to distribute requests. You can adjust the performance of IBM Cognos Platform by defining how IBM Cognos Dispatcher handles requests and manages services.

Threads within IBM Cognos Platform are managed by the type of traffic that they handle, which is referred to as high and low affinity. Affinity relates to the report service process that handled the original user request when multiple interactions need to occur to satisfy the request. High-affinity connections are used to process total and high-affinity requests from the report services. Low-affinity connections are used to process low-affinity requests. A high affinity request is a transaction that can gain a performance benefit from a previously processed request by accessing cache. It can be processed on any service, but resource consumption is minimized if the request is routed back to the report service process that was used to execute the original process. A low affinity request operates just as professionally on any service.

IBM Cognos configuration: A normal configuration for IBM Cognos Dispatcher is two IBM Cognos Report Server processes allocated processor and eight to 10 threads per processor in one of the following configurations:

• Three low affinity threads plus one high affinity thread 
• Four low affinity threads plus one high affinity thread

We can manage the number of threads per IBM Cognos BI reporting service process through the IBM Cognos Platform administration relieve by setting the number of high- and low-affinity connections

IBM Cognos Report Server
The main service that is responsible for application-tier processing is the report or query service .IBM Cognos Dispatcher starts IBM Cognos Report Server processes animatedly as needed to handle the request load. An administrator can identify the maximum number of processes that these services can start, as well as the minimum number of processes that should be running at non-peak times. arrange the number of processes for IBM Cognos Report Server based on the available processor capacity.

In general, IBM Cognos BI reporting service performance is closely tied to processor clock speed and throughput capabilities. The number of processors in a server and their clock rates are the two primary factors to consider when planning for additional IBM Cognos Report Server hardware capacity. For example, you generally configure a server with four available processors to use more report service processes than a server with only two available processors. Similarly, given two servers with an equal number of processors, configure the server with a considerably faster processor clock rate to have more report and report-service processes.

When configuring the IBM Cognos Platform server environment, you must set a Java heap size. The IBM Cognos BI reporting and query service is made up of two underlying components: 

• The Java servlet-based IBM Cognos Dispatcher services 
• Report services that are launched using the Java Native Interface (JNI)

Set the Java virtual machine (JVM) heap-size allocation for IBM Cognos Platform so that Java memory is only as large as is necessary to accommodate the processing requirements of the Java based services. This setting ensures that as much memory as probable is available to the IBM Cognos Report Service, which is not Java. You can decide the optimal Java heap size using Java garbage collection statistics.