Custom properties modify the application placement controller configuration. You can use these settings to tune the application placement controller behavior beyond the settings that are in the administrative console.
Use the cpuUtilizationThreshold custom property to define the percentage of CPU power that you can use on each node in a cell.
The cpuUtilizationThreshold custom property defines the percentage of CPU power that is used on the nodes in your environment. The default value is 100, which means that 100% of the CPU can be used on each node in the cell. For configurations that involve z/OS nodes, you must set this value to less than 100.
The application placement controller attempts to compute placements so that the utilization of any node does not exceed the defined threshold. The application placement controller considers all processes, including processes that are not related to WebSphere Application Server or WebSphere Extended Deployment when making these calculations.
Use the GenerateUniquePorts custom property to generate unique ports for each dynamic cluster member.
default (z/OS) | false Attention: If vertical stacking is
enabled for a z/OS dynamic cluster, the port allocation strategy is forced
to true, to generate unique ports for each dynamic cluster member.
|
default (distributed platforms) | true |
Use the HttpSessionRebalanceOff custom property to disable HTTP session rebalancing.
With WebSphere Extended Deployment Version 6.0 or later, HTTP session rebalancing is automatically enabled. You can use HTTP session rebalancing to reassign existing session affinities to new servers that become available for processing the given Web application. See HTTP session rebalancing for more information.
Use the HttpSessionRebalanceOff custom property if you want to return your configuration to the old HTTP session behavior, where session affinities are established with a particular application server and are not reassigned to any new servers that become available.
You might consider disabling HTTP session rebalancing if your session sizes are large. If your sessions are large, the cost of moving the sessions to a new server might be more than the benefit of taking the workload off of the original server. You can use Performance Monitoring Infrastructure (PMI) data to make the decision to turn off session rebalancing. You might see in your PMI data that response time, memory utilization, and CPU utilization increases on specific servers to transfer the session information. See the WebSphere Application Server Network Deployment Information Center for more information about analyzing PMI data and best practices for using HTTP sessions.
If you leave session rebalancing on, as sessions become more evenly distributed, and memory and CPU utilization also become more evenly distributed across the servers in the cluster. If a cluster is more balanced, it is easier for WebSphere Extended Deployment to make autonomic decisions.
Perform the following steps to disable HTTP session rebalancing:
To turn session rebalancing back on, delete the custom property.
Under the default operation, the application placement controller profiles dynamic clusters online to determine their memory usage. You can disable this default operation by setting the memoryProfiler.isDisabled custom property to true. When the memory profiler is disabled, the application placement controller assumes a default memory usage value. This memory usage value is computed as 64k + 1.2 maxHeapSize, where maxHeapSize is the maximum heap size setting in the server template of the dynamic cluster.
Use this custom property to define the number of dynamic cluster instances on a node.
Use this custom property only if the nodes in your dynamic cluster are heterogeneous and vary in power. If the nodes in your dynamic cluster are homogenous, you can define the number of dynamic cluster instances one time in the administrative console.
See Configuring vertical stacking for more information.
Use this custom property to stop dynamic cluster instances during periods of inactivity.
This custom property adds function to the Stop all instances during periods of inactivity setting in the administrative console. With the administrative console setting, instances stop only if other clusters in the cell need the resources that are being used by the inactive instances. You also specify an amount of time to wait before stopping instances for the cluster. By setting this custom property, inactive instances stop even if the resources are not required elsewhere in the environment. The custom property goes idle in the amount of time that you specified in the administrative console setting.
You can set this custom property on all dynamic clusters by creating the custom property on the cell level. You can also create the custom property on a single dynamic cluster. If the property is set on both the cell and the dynamic cluster, the dynamic cluster setting is used.
Use these custom properties to define how much memory on each node to reserve for processes that are not related to WebSphere Application Server or WebSphere Extended Deployment.
reservedMemoryFixed + reservedMemoryPercent * (totalNodeMemory - reservedMemoryFixed)
Property name | Definition | Default |
---|---|---|
reservedMemoryFixed | A fixed amount of memory to reserve. | 64 MB |
reservedMemoryPercent | A percentage of memory to reserve. | 5% |
Use this custom property to define a replacement to the reservedMemory default custom property. It will use the node's free memory statistic, plus the memory calculated for any dynamic cluster instances already residing, to calculate the memory available for launching additional DC instances.