To supplement standard alarms (which Rhino and installed components raise), an administrator may configure custom alarms (which Rhino will raise or clear automatically based on SLEE Statistics.

These are known as threshold alarms, and you manage them using the Threshold Rule Management MBean.

Threshold rules

You configure the threshold rules governing each threshold alarm using a Threshold Rule MBean.

Each threshold rule consists of:

  • a unique name identifying the rule

  • one or more trigger conditions

  • an alarm level, type and message text

  • and optionally:

    • one or more reset conditions

    • how long (in milliseconds) the trigger conditions must remain before Rhino raises the alarm

    • how long (in milliseconds) the reset conditions must remain before Rhino clears the alarm.

Tip You can combine condition sets using either an AND or an OR operator. (AND means all conditions must be satisfied, whereas OR means any one of the conditions may be satisfied — to raise or clear the alarm.)

Parameter sets

Threshold rules use the same parameter sets as the statistics client. You can discover them either by using the statistics client graphically or by using its command-line mode from a command shell as shown below.

To list all available parameter sets:
$ ./rhino-stats -l
The following root parameter sets are available for monitoring:
Activities, ActivityHandler, ByteArrayBuffers, CGIN, DatabaseQuery, Diameter,
EndpointLimiting, EventRouter, Events, HTTP, JDBCDatasource, JVM, LicenseAccounting,
Limiters, LockManagers, MemDB-Local, MemDB-Replicated, MemDB-Timestamp, Metrics,
ObjectPools, SIP, SIS-SIP, SLEE-Usage, Services, StagingThreads, StagingThreads-Misc,
TimerFacility, TransactionManager

For parameter set type descriptions and a list of available parameter sets use the
-l <root parameter set name> option
To list the statistics collected by the JVM parameter set:
$ ./rhino-stats -l JVM
Connecting to localhost:1199
Parameter Set: JVM
Parameter Set Type: JVM
Description: JVM Statistics

Counter type statistics:
  Id: Name:                 Label:      Description:
  0   heapUsed              husd        Used heap memory
  1   heapCommitted         hcomm       Committed heap memory
  2   heapInitial           hinit       Initial heap memory
  3   heapMaximum           hmax        Maximum heap memory
  4   nonHeapUsed           nhusd       Used non-heap memory
  5   nonHeapCommitted      nhcomm      Committed non-heap memory
  6   nonHeapInitial        nhinit      Initial non-heap memory
  7   nonHeapMaximum        nhmax       Maximum non-heap memory
  8   classesCurrentLoaded  cLoad       Number of classes currently loaded
  9   classesTotalLoaded    cTotLoad    Total number of classes loaded since JVM start
  10  classesTotalUnloaded  cTotUnload  Total number of classes unloaded since JVM start

Sample type statistics: (none defined)

Found 1 parameter sets under 'JVM':
    ->  "JVM"

How Rhino evaluates threshold rules

Rhino periodically evaluates the trigger conditions of each configured rule. When a trigger condition is satisfied and its trigger period has been met or exceeded, Rhino raises the corresponding alarm. If the rule has reset conditions, Rhino evaluates those too, and when the reset condition is satisfied and the reset trigger period has been met or exceeded, clears the alarm. If the rule does not have reset conditions, an administrator must clear the alarm manually.

You can configure the frequency of threshold alarm rule evaluation, using the Threshold Rule Management MBean. An administrator can specify a polling frequency in milliseconds, or enter 0 to disable rule evaluation. The Rhino default is 0 (which must be changed to enable threshold-rule evaluation). Ideal polling frequency is highly dependent on the nature of alarms configured.

Simple and relative rule conditions

There are two types of threshold rule conditions, explained in the tables below.

Simple rule conditions

What it compares Operators for comparison Conditions Example

The value of a counter-type Rhino statistic against a constant value.

 
 >, >=, <, <=, ==, !=

The constant value to compare against may be any floating-point number. The condition can either compare against the absolute value of the statistic (suitable for gauge-type statistics), or against the observed difference between successive samples (suitable for pure counter-type statistics).

A condition that selects the statistic rolledBack from the Transactions parameter set, and evaluates to true when the number of transactions rolled back is > 100.

Relative rule conditions

What it compares Operators for comparison Conditions Example

The ratio between two monitored statistics against a constant value.

 
 >, >=, <, <=, ==, !=

The constant value to compare against may be any floating-point number.

A condition that selects the statistics freeMemory and totalMemory from the SystemInfo parameter set, and evaluates to true when free heap space is less than 20% of total heap space. (Using the < operator and a constant value of 0.2, the condition would evaluate to true when the value of freeMemory / totalMemory is less than 0.2.)
Note For definitions of counter, guage and sample type statistics, see About Rhino Statistics.
Tip
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Rhino Version 3.0.0