AutonomicRequestFlowManager

Autonomic Request Flow Manager resides in the On Demand Router and controls how requests are prioritized as they are dispatched to the Application Servers. This object contains the configuration parameters that are used for each nodegroup within the cell.



Attributes Summary
controlCycleMinimumLength : intThis parameter defines how often the ARFM controller is activated.
controlCycleMinimumLengthUnits : intThis parameter defines how often the ARFM controller is activated.
maximumQueueLength : intThis parameter is used to bound the length of each ARFM queue to a maximum number of requests that may be held in queue.
maximumCPUUtilization : intThe ARFM provides overload protection, in addition to its prioritization capabilities.
smoothingWindow : intThis setting defines how sensitive the ARFM controller reaction is to the incoming gateway statistics, by allowing a concatenation of gateway statistics.
aggregationPeriod : intEach ARFM gateway broadcasts aggregated statistics periodically, and this parameter, along with the aggregationPeriodUnits, specifies the period.
aggregationPeriodUnits : intEach ARFM gateway broadcasts aggregated statistics periodically, and this parameter, along with the aggregationPeriod, specifies the period.
properties : Property *  

Attribute Details

controlCycleMinimumLength    -    This parameter defines how often the ARFM controller is activated. Controller activation is the process of evaluating inputs and producing new control settings as a result of the input received. The activation process for an ARFM controller is initiated when new statistics are received from one of its gateways AND the elapsed time since the previous activation is greater than or equal to the control cycle minimum length, or the controller has never activated before. This parameter is set in concert with the controlCycleMinimumLengthUnits, which together make up the time period.There is one setting to be aware of before setting the control cycle length minimum. If you have just one ODR and set the aggregation period to 30 seconds and the control cycle minimum length to 60 seconds, you might find that one activation occurs at 12:00:00.0 and the next occurs 90.1 seconds later at 12:01:30.1 because the previous statistics arrival time was 12:00:59.9. To ensure a reliable control cycle of around 60 seconds, you would set the control cycle minimum length to 58 or 59 seconds.
     data type:  int
     default Value:   59



controlCycleMinimumLengthUnits    -    This parameter defines how often the ARFM controller is activated. Controller activation is the process of evaluating inputs and producing new control settings as a result of the input received. The activation process for an ARFM controller is initiated when new statistics are received from one of its gateways AND the elapsed time since the previous activation is greater than or equal to the control cycle minimum length, or the controller has never activated before. This parameter is set in concert with the controlCycleMinimumLength, which together make up the time period. This parameter is stored as an integer representation of the units, where UNITS_SECONDS = 1, UNITS_MINUTES = 2, and UNITS_HOURS = 3. Those are the 3 allowable values for this parameter.
     data type:  int
     default Value:   1



maximumQueueLength    -    This parameter is used to bound the length of each ARFM queue to a maximum number of requests that may be held in queue. ARFM has a separate queue for each combination of ODR(s), node group(s), service class(es), and deployment target(s). When a request arrives and the queue is full, the request is rejected. A lower parameter in this field increases the possibility that a request will be rejected due to short-term traffic bursts, while a higher parameter in this field may allow requests to linger longer in the queues. Queued requests consume memory. The default setting is 1000, but you may want to experiment with this setting to find the one that is a best match for your environment. The value of maximumQueueLength should be in the range 1 through 2147483647
     data type:  int
     default Value:   1000



maximumCPUUtilization    -    The ARFM provides overload protection, in addition to its prioritization capabilities. An ARFM will queue requests in its gateways to avoid overloading the application servers. For this release, load is determined in terms of CPU utilization on the first tier of application servers. The maximum CPU utilization parameter tells ARFM how heavily to load the servers. During severe peak conditions this utilization limit may be exceeded briefly. This value must be in the range 1 through 100.
     data type:  int
     default Value:   90



smoothingWindow    -    This setting defines how sensitive the ARFM controller reaction is to the incoming gateway statistics, by allowing a concatenation of gateway statistics. For any gateway, its ARFM controller uses a running average of the last few statistics reports from that gateway. The smoothing window controls the number of reports that are combined. A low smoothing window setting will make the controller more sensitive and will allow a quicker reaction. However, a low parameter will also create a sensitive reaction to noise, or anomalies, in the data. Note: It is recommended that the product of the smoothing window and the aggregation period be roughly the same as the actual control cycle length, which will sometimes be slightly greater than the configured control cycle minimum length.The value of the smoothingWindow must be in the range 1 through 1000.
     data type:  int
     default Value:   12



aggregationPeriod    -    Each ARFM gateway broadcasts aggregated statistics periodically, and this parameter, along with the aggregationPeriodUnits, specifies the period.When setting the aggregation period, ensure the value is high enough to allow for the collection of a sufficient number of performance samples. Samples are collected by the gateway(s) for each HTTP request. A few hundred samples are necessary to produce a good statistical measure. Using an example - requests associated with a service class execute in 250 milliseconds, and on average 10 requests are executed concurrently. (The concurrency value is calculated automatically by WebSphere Extended Deployment, based on the cluster size and the resources in the environment. The concurrency value can be seen on the visualization panels, under the Runtime Operations category in the console.) As a result, the service class will handle about 40 requests per second. Therefore, setting the aggregation period value to 15 seconds will result in the collection of 600 samples for each aggregation period. The metrics provided by a 600 sample survey are useful and reliable.Setting an aggregation period value too low will result in unreliable performance metrics. Performance metrics derived from fewer samples are more noisy and less reliable, then a higher sample size. Because the ARFM controller is activated when new statistics are produced, setting an aggregation period value too long results in less frequent recomputation of the control settings. Therefore, WebSphere Extended Deployment becomes less responsive to sudden changes in traffic intensities and patterns.
     data type:  int
     default Value:   5



aggregationPeriodUnits    -    Each ARFM gateway broadcasts aggregated statistics periodically, and this parameter, along with the aggregationPeriod, specifies the period.
     data type:  int
     default Value:   1



properties    -     
     data type: Property*


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