9.2 Dynamic reconfiguration managerAn AIX 5L subsystem known as the Dynamic Reconfiguration manager (DR manager) executes change requests for dynamic LPAR resources and notifies applications about resource changes in the partition. By default, an application does not receive any information about changes in the resources; instead, the application has to register itself explicitly in order to receive such resource change notifications.
The resource change notification is referred to as a dynamic reconfiguration event (DR event). A DR event can be related to memory, CPU, or PCI I/O slot. It is the responsibility of the DR manager to fulfill the DR event request. The DR manager notifies registered applications at various stages of the DR event.
When notified, the applications can take the necessary actions to maintain integrity and scalability with either an increase or a decrease in available resources. An application registers to receive DR event notifications by installing a DR script through the drmgr command (for installing and configuring DLPAR), or by trapping a newly introduced SIGRECONFIG signal.
Another alternative is for the application to poll a partition periodically. WebSphere XD implementation is based on the polling mechanism.
WebSphere XD can only benefit from the memory and CPU resource changes.