Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS
Configure application lazy start
By configuring application lazy start, you can release resources that are being consumed by inactive dynamic clusters so that other cluster instances in the cell can use these resources.
Before you begin
- Application lazy start requires that requests are routed through the on demand router. To create an on demand router, see Creating ODRs for more information.
- IIOP and Java™ Message Service (JMS) requests cannot be used because they are not routed through the ODR. Do not use application lazy start on dynamic clusters that run Session Initiation Protocol (SIP) applications.
- Create a dynamic cluster. See Creating dynamic clusters for more information. You can also configure application lazy start when you are creating a dynamic cluster.
About this task
An application lazy start is the activation of the first application server instance of a deactivated dynamic cluster when an application request arrives. You decide which applications to deactivate and subsequently lazily start. Use application lazy start if you have an environment in which the ratio of the number of dynamic clusters to the number of nodes is high, and if many dynamic clusters are not accessed for a long period. By using application lazy start, you can increase the performance and efficiency of your environment.
Procedure
- Edit the dynamic cluster properties. In the administrative console, click Servers > Dynamic clusters > dynamic_cluster_name .
- Select the If other dynamic clusters need resources, stop all instances of this cluster during periods of inactivity option.
- Set the Time to wait before stopping instances in minutes if the application placement controller determines that the resource is required by some other dynamic application cluster.
Results
The application placement controller tracks the amount of time that a dynamic cluster has been inactive. If another dynamic cluster needs resources, the application placement controller can stop the inactive dynamic cluster after the specified time period. The resources that were consumed by the inactive instance are released and made available for use by the dynamic cluster that requires additional resources. If a request arrives for the stopped dynamic cluster instance, the lazy start controller is activated and at least one server instance is started. In the meantime, HTTP error code 503 (server unavailable) is generated. The error page informs you that the requested application is starting and the request is resubmitted shortly.
What to do next
- Application lazy start only stops dynamic cluster instances if other dynamic clusters need resources. If you want to stop dynamic cluster instances after the specified time period even if the resources are not needed, configure the proactiveIdleStop custom property.
- You can configure a custom error page for the ODR that can be used for the 503 error. The error page can include an HTTP meta refresh tag that causes the browser to automatically send the request again after a certain waiting period. See Configure ODRs for more information about configuring custom error pages.
Subtopics
Application lazy start
Related concepts
Dynamic clusters
Related tasks
Creating dynamic clusters
Related reference
Dynamic cluster administrative tasksRelated information
Application placement custom properties