5.8.5

Table Of Contents
Option Description
Entire range
Sets the time range to analyze as the range defined in the Manage Display
Settings section of the Configuration dialog box.
Consider allocation in stress
calculation
Enables an allocation model in calculating stress. Allocation considers
allocated resources as used, and unallocated resources as capacity
remaining.
4 Click OK or Finish to save your settings, or select another option to configure.
5 Click Done to close the Configuration dialog box.
The criteria for underused and stressed capacity are reconfigured.
Determining the Underused and Stressed Capacity Thresholds
You determine the thresholds for underused and stressed capacity on ESX hosts and clusters to define what
is acceptable in your virtual environment.
You can set the underused and stressed capacity thresholds in the 4 Configure state-related thresholds
section of the Edit Policy dialog box.
You determine the time period for which values are computed by using the Usage Work Week setting in the
3c Usage calculation section. By default, vCenter Operations Manager uses a 24-hour period, 7 days a week,
but you can modify this setting. The following examples use the default usage calculation setting.
Underused and stressed capacity thresholds represent the degree to which you allow the resources to be
underused or stressed. Underused and stressed capacity thresholds are computed as an area ratio between
the demand area in the stressed zone and the area of the stressed zone.
Example: Calculating the Thresholds for a Stressed or Underused Resources
To set the thresholds for a one-week interval, open the Configuration dialog box and click Manage Display
Settings. Set the Non-Trend Views Interval to Weekly and select 1 as the number of intervals to use.
You set the percentage of affordable stress or underuse in the 4c Underused and stressed section of the Edit
Policy dialog box. Determine the area ratio for which you can afford to have high stress or low use in your
environment.
To determine the stress threshold for a day, multiply the stress area ratio by 100.
Demand in the stress zone/stressed zone * 100
For stress, even an hour or two per week might represent a problem, because during that time the capacity
is almost exhausted. Therefore, you can set a peak time period as well as the stress threshold, and specify
the maximum number of hours that can have stress levels above the specified threshold.
By setting this peak period, you define a "moving window" of a number of hours, and the stress calculation
will be applied to every such window in the Non-Trend Views Interval. The stress calculation is:
stressed % = max_(for each moving window)(demand area in the stress zone in the window/area of
stressed zone in the window)
Example: Calculating the Thresholds for Underused and Stressed Resources for Four Weekly
Intervals
To set the thresholds for four weekly intervals, open the Configuration dialog box and click Manage
Display Settings. Set the Non-Trend Views Interval to Weekly and select 4 as the number of intervals to
use.
Example: Limiting the Thresholds for Business Days and Hours
To restrict the stress limit to 8 business hours, Monday to Friday, specify the hours and days in the 3c Usage
calculation section of the policy configuration dialog box.
Chapter 8 Set How Data Appears in vCenter Operations Manager
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