Essbase Clustering #
What is Essbase Server Clusters? #
Essbase Enterprise Services allow you to group sets of Essbase servers running applications with identical databases and use them as a single resource in the client programs.
Before using Essbase servers with Essbase Enterprise Services, configure the Essbase servers for use with Essbase Enterprise Services to better support concurrent usage, create replicas of your application, and create users. In order to configure these settings, modify the essbase.cfg file located in the ARBORPATH\bin directory of the Essbase server installation.
Clustering of servers enables features such as load balancing and failover support:
Load balancing enables redistribution of requests across a cluster of Essbase servers running identical databases to guarantee consistent performance under load.
Failover support detects service interruptions in a cluster, and reroutes requests to other available Essbase servers in a cluster. You must restart the server to reflect changes to the cluster.
To define a cluster #
- In the navigation panel, select a domain under Domains or select Clusters if clusters have already been created.
- Right-click, then select Create > Cluster.
- In the dialog that is displayed, type the name for your cluster; for example, mycluster.
- Click OK.
- In the navigation panel, select the cluster that you have just created.
- In the cluster’s properties panel, set the service component name; for example,localhost/Demo/Basic;localhost/Demo2/Basic.
- Click Save.
- Specify the cluster name in the properties panel of the Enterprise Server for which you want to associate the cluster.
Clustering Modes #
There are 2 types of Clustering
- Active-Passive Clustering (Vertical)
- Active-Active Clustering (Horizontal)
Summary Essbase Server Clustering Method
Active-Passive Clustering (Vertical) #
Clustering where multiple instances of Essbase are created on the same machine (adding more hardware). This can be configured using EPM System Configurator. It can contain only two Essbase servers. To install an additional Essbase server, install an additional instance of Essbase on another machine. The applications must be on a shared drive, and the cluster name must be unique within the deployment environment. It consists of two Essbase instances, one on each node that shares a common storage for configuration and data. Storage is shared across two computers.
These types of shared drive are supported:
- SAN storage device with a shared disk file system supported on the installation platform such as OCFS
- NAS device over a supported network protocol.
An Active-Passive Essbase cluster provides automatic failover, high availability and write-back to databases. It does not support Load-Balancing.
Essbase failover clusters can be implemented using EPM System Configurator. It uses the service failover functionality of OPMN. Failover A single Essbase installation is run in an Active-Passive deployment, and one host runs the Essbase agent and two servers. Only one agent can be active at any given time. OPMN stops, starts, and monitors the agent process.
Active-Active Clustering (Horizontal) #
Clustering where the exact replica of the Essbase server is spread across multiple machines where each machine is in active state. This can be configured using Provider Services.
Essbase Clustering Options using Provider Services, you can create a cluster of identical databases belonging to one Essbase server, to multiple Essbase servers on the same computer, or to Essbase servers distributed across multiple computers over the network.
If Essbase is clustered with Provider Services and no third-party tool:
- Smart View must be used rather than an Excel add-in.
- Essbase has no write-back capability and should be used for reporting only; therefore, Oracle Hyperion Planning, Fusion Edition is not supported.
- Nodes must be loaded and calculated individually.
Active-active Essbase cluster support:
- High Availability
- Load Balancing
- Read-Only operations on the databases which should be used only for reporting
Active-Active Essbase clusters do not support data write-back or outline modification, and they do not manage database replication tasks such as synchronizing the changes in one database across all databases in the cluster, they do not support Planning. When Planning is configured to use Essbase in cluster mode as a data source, it does not support the ability to launch business rules with Calculation Manager as the rules engine.
You can implement active-passive failover using EPM System Configurator, or active-active failover using Provider Services, but not both.
Provider Services #
Provider Services is a middle-tier data-source provider to Oracle Essbase for Java API, Smart View, Fusion Edition, and XMLA clients and to OBIEE.
To sum up, Provider services allow the following:
- Distribute users requests to database instances belonging to the cluster.
- Enable you to group sets of Essbase servers running applications with identical databases and use them as one resource.
- Provide parallel clustering, in which a series of active, duplicate databases respond to users requests.
- Database access and connection is transparent to users. User will not know which database it has access to.
- Provider Services facilitates the routing of connections between databases in a cluster, based on availability and precedence rules.
User connects to Essbase through Provider Services. Each user connection is assigned to a server during the Essbase session. Provider Services uses session-level load balancing.
Following example is based on Smart View.
User 1 connection map to Data Source A. User 2 connection to Data Source B. User 3 connection map to Data Source C. All requests from User 1 are handled by Data Source A for the duration of the connection.
Case 1 #
Issue:
- Data Source A fail.
- Database Cluster with One Data Source Offline. Data Source A goes offline.
Action:
- User 1 time out at Data Source A and rerouted to the next available data source, which is Data Source C
The state of query 1 is maintained at the middle tier and rerouted. Provider Services also provides load balancing across servers.
The Essbase Database Cluster deployed on One Server. The diagram below shows two servers contain Essbase databases. Because Server 2 has more resources, it contains Data Sources B and C. Therefore, Server 2 can handle both connections.
Failover support also applies for database clusters on one server.
Case 2 #
Issue:
- Server 2 goes offline
Action:
- User 2 and User 3 are then rerouted to the next available server, Server 1.
Refer to attached PDF for OBIEE 11g Scaleout & Clustering