Workload Distribution 

Use

With workload distribution you can optimize the stability, availability and load of your portal. It is a mechanism for assigning specific content-driven workload to sub-topologies of the J2EE Engine cluster setups – the zones. It is based on the handling of external requests. A zone consists of one or more J2EE instances. An instance consists of a J2EE Engine Dispatcher and one or more application servers.

You isolate certain parts of the portal that can cause problems. By assigning a topic to a zone, the corresponding code can be entirely isolated from other code parts with respect to session management, server-side eventing, etc.  You define zones (one or more server nodes) in your J2EE cluster environment. You then assign these zones portal content (J2EE applications, portal applications, roles, worksets, pages or iViews) from the portal system administration.

No zones are set up by default – the portal content executes on all cluster nodes. You should set up workload distribution if certain parts of the portal endanger the stability or load of the portal. We recommend this especially for custom developments.

The content administrator will normally assign portal content to zones.

Features

You can assign portal content to zones according to certain criteria. The following groups (classes) are available:

Portal Content	Assignment
Portal Component	A certain portal component is assigned.
Portal Application	All elements of a certain portal application, including the portal components it contains, are assigned.
Context	The object ID of a folder structure in the Portal Catalog (PCD path) is assigned. All the elements of a folder structure are thus mapped to a zone.
Topic	All iViews whose property Work Distribution Topic has a certain value are assigned. The property is maintained in the Property Editor.

 

At portal runtime, the distribution mechanism identifies the zone specification from the incoming request. The SAP Web Dispatcher handles the incoming requests. When it accepts a connection, it sends the request to the assigned server node and distributes the load across the servers and zones in order to insure equal distribution. The following rule is valid when determining the zone:

...

       1.      Portal Component

       2.      Portal Application

       3.      Context

       4.      Topic

The portal component criterium is first checked. If there is no valid assignment, the remaining criteria are checked in the listed order.

If no assignment is found, the portal content is executed on a random cluster.

If the content is not allowed for a zone, an error message is displayed in the portal. This message also appears if portal content is not correctly assigned to zones (e.g. in case of inconsistencies).

There is an inconsistency if Zone za is assigned to a page, but this page contains an iView that is assigned to Zone zb with the property Work Distribution Topic.

By default the error message iView DedicationAlerter of portal component sap.com.portal.supportability.isolde is called. You can display a different iView (e.g. with your own error message text).

For detailed information about the configuration read Defining Workload Distribution.

Workload distribution is only possible for URL isolated iViews. Embedded iViews are not supported at the moment. For more information see Isolation Method of iViews.