Autonomic request flow manager custom properties

You can use the following custom properties to change the behavior of the autonomic request flow manager (ARFM). Some custom properties are set on deployment targets.

CenterCell custom property

When you are configuring multi-cell performance management in your environment, you can use the CenterCell custom property to designate one cell as the center cell. You also set the CenterCell custom property individually for each cell that you want to designate as a point cell.

Avoid trouble Avoid trouble: One and only one custom property should be set to true.gotcha
Table 1. CenterCell custom property values
Value Description
Scope Cell
Valid values true: Designates one cell as the center cell

false: Designates one cell as a point cell

enableRateBasedARFM

ARFM uses a rate-based algorithm that results in a more consistent loading and protecting of application server resources. The rate-based ARFM feature is enabled by default. To disable the feature, set the enableRateBasedARFM custom property to false.

Table 2. AC5.BurstFactor custom property
Value Description
Scope Cell
Valid values Boolean
Default False

AC5.BurstFactor

You can set this value to change how tolerant memory overload protection (MOP) is to bursts of traffic. If the maximum rate is one unit per second and the burst factor is one, then one unit of non-affinity traffic is admitted if it did not admit one in the last second. If the burst factor is three however, it admits three units every three seconds.

Table 3. AC5.BurstFactor custom property
Value Description
Scope On demand router
Valid values Integer
Default 3

arfmIgnoreHttpSessionsForCpu

You can set this custom property to true so that the ARFM ignores the HTTP dialog structure for the purposes of CPU overload protection. Every incoming HTTP message is subject to admission control.

Table 4. arfmIgnoreHttpSessionsForCpu custom property
Value Description
Scope Cell
Valid values Boolean
Default False

arfmIgnoreSipDialogsForCpu

You can set this custom property to true so that the ARFM ignores the Session Initiation Protocol (SIP) dialog structure for the purposes of processor overload protection. Every incoming SIP message is subject to admission control.

Table 5. arfmIgnoreSipDialogsForCpu custom property
Value Description
Scope Cell
Valid values Boolean
Default False

arfmManageCpu

CPU overload protection is on by default. Set the value of this custom property to false to disable CPU overload protection and request prioritization.

Table 6. arfmManageCpu custom property
Value Description
Scope Cell
Valid values Boolean (true or false)
Default True

arfmManualAllocation

You can specify this custom property on a deployment target to put ARFM into manual mode when the custom property arfmMode is not set to manual. The value of the property is a string in a syntax that allows expression of allocations.

Table 7. arfmManualAllocation custom property
Value Description
Scope Deployment target (server, dynamic cluster, and so on)
Valid values String
Default No default

arfmMode

You can use this custom property to specify the operating mode of the ARFM. In automatic mode, the ARFM has an autonomic controller that adjusts the dispatching priority of requests from the on demand routers to the servers and sends the placement controller information about the computational needs for the various dynamic clusters. In manual mode, you can override the autonomic controller with administrative settings.

Table 8. arfmMode custom property
Value Description
Scope Cell
Valid values Manual, Automatic
Default Automatic

CPUAdjustment

You can set this custom property on nodes that are on hyperthreaded computers. When the CPUAdjustment custom property is specified on a node, a correction function to apply to processor utilization readings is specified for that node. This function is applied to the processor utilization that is reported by the operating system, and yields a more accurate utilization measure.

Table 9. CPUAdjustment custom property
Value Description
Scope Node
Valid values String
Default No default

goodServiceTimeLimitSpec

Use a goodServiceTimeLimitSpec custom property when configuring the ARFM. The default value of one minute for determining timeouts is used if goodServiceTimeLimitSpec or timeoutFactor is not set. To override the default, set this custom property to customize the value for different levels of granularity. For example, service class, application, or module. To create a general rule of 5 minutes, create the custom property and set the value to "*:*:*:*:*=300" where the last part is the timeout value of 300 seconds. The timeout value is a decimal number, not necessarily a whole number, and is in units of seconds.

Table 10. goodServiceTimeLimitSpec custom property
Value Description
Scope Cell
Valid values Decimal number in unit of seconds
Default 60 if timeoutFactor is not set. Otherwise, no default.

magicNMode

You can set this custom property when ARFM is in automatic mode. When in automatic mode, concurrency limiting is performed according to one of two criteria, depending if the magicNMode custom property is enabled. When the magicNMode custom property is enabled, the total number of requests that are running concurrently at any given time is limited to a certain total. In normal mode, the total number of requests depends on the use of processor power on the nodes.

Table 11. magicNMode custom property
Value Description
Scope Cell
Valid values Boolean
Default False

magicN

You can use this custom property when ARFM has the magicNMode custom property is enabled, to the limit on the total number of concurrent requests. If this property is not defined, a reasonable limit is estimated from other data.

If you are using the reasonable limit estimation, the limit on the total number of concurrent requests for a cell is the sum of a contribution from each node in the cell. The contribution from a node is the average, over the running application servers on that node, of the maximum size of the thread pool of the Web container on that application server.

Table 12. magicN custom property
Value Description
Scope Cell
Valid values A positive integer defines the number of concurrent requests. To use the reasonable estimate, set the property value to a negative number or delete the custom property.
Default -1

maxHttpLiveRequests

You can use this custom property to define the maximum number of requests that are targeted for a particular cell and could be anywhere in the cell. That is, either queued in an ODR or running on an application server at a given time.

Table 13. maxHttpLiveRequests custom property
Value Description
Scope Cell
Valid values Integer
Default No default

MOP.AveragingWindowInMS

The averaging window in milliseconds that is used by MOP. This time interval should be at least as long as the lifetime of 95 percent of the HTTP sessions, SIP dialogs, and application sessions. If the time interval is too short, MOP might not protect against memory overload. If the time interval is much longer than the lifetime of these objects, MOP still protects against memory overload but MOP takes a longer amount of time to ramp up to learn the maximum rate.

Table 14. MOP.AveragingWindowInMS custom property
Value Description
Scope Cell
Units milliseconds
Default 180000 ms

MOP.InitialMaxRatePerSec

If no persisted maximum rate value exists, the value of this custom property is used as the initial maximum rate.

Table 15. MOP.AveragingWindowInMS custom property
Value Description
Scope Cell
Default 1

node.speed

You can use this property to define the node speed in MHz. Set the value to the processor speed, multiplied by the number of processors on a multi-processor node. Set this custom property on the node.

Table 16. node.speed custom property
Value Description
Scope Node
Valid values A floating point number that represents the number of MHz of the reference instruction set.
Default No default

node.memory

You can use this property to specify the available RAM defined in megabyte units on a node. Set this custom property on the node. Although this value is determined automatically, you can override the value.

Table 17. node.memory custom property
Value Description
Scope Node
Valid values A number of megabytes
Default No default

node.numCPUs

You can use this custom property to specify the number of processors on a multi-processor node. This value is automatically determined, but you can override the value. Set this custom property on the node.

Table 18. node.numCPUs custom property
Value Description
Scope Node
Valid values Integer that represents the number of processors
Default No default

timeoutFactor

Specify the timeoutFactor custom property to indicate a value that is multiplied by the response time threshold to determine the fine-grained timeout threshold. Use a timeoutFactor custom property when configuring the ARFM. The timeoutFactor value is multiplied by the response time threshold to yield the fine-grained timeout threshold.

This fine-grained timeout threshold is one of three different factors that the ARFM uses to determine that a running request has timed out. The running request has timed out when one of the following factors is true:
  • The proxy framework indicates the request timed out.
  • The request reply includes a special HTTP header that indicates that the internal application timed out.
  • The service time exceeds the fine-grained timeout value.
Table 19. timeoutFactor custom property
Value Description
Scope Cell
Valid values Decimal representation of a floating point number
Default No default

useODRs

Specifies if the work profiler and placement controller rely on the services of the ODR servers.

Table 20. useODRs custom property
Value Description
Scope Cell
Valid values Boolean
DefaultRT True


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