User guide

5-32 ExtremeWare EPICenter Software Installation and User Guide
The EPICenter Alarm System
•StartupAlarm: The Startup condition is predefined to be Rising.
• Sample Interval: The sample interval for a CPU Utilization alarm is also predefined,
and is set to 3 seconds.
•SampleType: The sample value (a percentage) is always an absolute value.
It is important to understand that, except for the initial occurrence of a Rising Threshold
alarm, a CPU Utilization alarm will be generated only the when the sample value of the
variable crosses the target threshold for the first time after having crossed the other
threshold.
The diagram shown in Figure 5-14 illustrates how CPU Utilization trap events will occur
once you have configured a CPU Utilization rising threshold. The startup condition for a
CPU Utilization event is always predefined to be Rising.
Figure 5-14: CPU Utilization event generation
ThefirstCPUUtilizationtrapoccursattheinitialsample value,since thevalueisabovethe
CPU Utilization Rising threshold. If the initial value were below the Rising threshold, no
event would occur.
The second event occurs at point X, because the sample value has fallen below the falling
threshold, which is defined as 90% of the rising threshold value. The third event occurs at
point A because the sample value is again above the Rising Threshold after having fallen
XM_023
Rising
threshold
Falling
threshold
(90% of
rising)
Initial
sample
value
Time (sample intervals)
Sampled
CPU
utilization
value
X
A
B
= alarm event generated
Y
Z
C