6.3

In vRealize Operations Manager, stress involves how high and how long the demand persists relative to the
capacity available, and vRealize Operations Manager uses this value to measure the potential for
performance problems. The higher the stress score, the worse the potential is for degraded performance on
your objects. Depending on the conguration of the policy analysis seings for stress, a score of green might
indicate 0–24 percent of stress. A score of red might indicate more than 50 percent of stress. With the ve-
minute data collections and the intelligent stress calculations, vRealize Operations Manager can easily
identify periods of poor performance.
Demand drives stress. vRealize Operations Manager bases the calculations for right-sizing capacity on past
demand. The goal of right-sizing is to produce a green level of stress, marked by a green Stress badge.
Usable capacity is equal to the total capacity available minus any buers that administrators or users
dened. To measure the right-sized amounts of usable capacity, the capacity calculations use what is called a
stress-free value. Using the demand, stress, and the stress-free value, vRealize Operations Manager
calculates the right size.
The capacity analytics determine the actual and eective demand for resources based on having no
contention. The calculations consider the capacity to be unlimited and free of contention for resources,
which results in no stress on the available capacity. The result is called the stress-free demand or the stress-
free value.
Where to Find Stress-Free Demand and Stress-Free Value
In some areas of the user interface, vRealize Operations Manager identies capacity as Stress Free Demand,
and in other areas it is identied as Stress Free Value. Both terms mean that the calculated capacity for an
object is free from unacceptable levels of contention and stress, as dened in the policy for the Stress score.
Stress Free Demand appears in Troubleshooting > All Metrics, Views, and Reports.
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In Troubleshooting > All Metrics, you can use the metric named Stress Free Demand to examine the
CPU demand, disk space allocation and demand, memory consumed, and the vSphere conguration
limit on an object. When you apply this metric to these resources, you can build a metric graph to
display the stress-free demand for an object. The graph displays the high and low stress-free capacity
values over time.
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In Content > Views, when you add or edit a view, in the Data and Conguration areas of the
workspace, you can use the metric named Stress Free Demand. Use this metric to build views for CPU
demand, disk space allocation and demand, memory consumed, and the vSphere conguration limit.
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In Content > Reports, you can use a view that includes the metric named Stress Free Demand to
generate a report. The table in the report displays Stress Free Demand as the label. For example, this
metric appears in the report named Cluster CPU Demand (%) Trend View.
Stress Free Value appears on the Object > Analysis > Time Remaining tab, and on the Object > Analysis >
Stress tab.
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On the Object > Analysis > Time Remaining tab, you can view the time remaining for CPU demand,
memory consumed, disk space demand and allocation, and the vSphere conguration limit. In this
view, the table column name is Stress Free Value.
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On the Object > Analysis > Stress tab, the table column name is Stress Free Value. The tables display
Stress Free Value as the calculated values for CPU demand, memory consumed, and the vSphere
conguration limit.
Setting the Thresholds for the Stress Score
The analysis seings in the policy that you apply to your objects denes the thresholds for the stress score.
The policy includes default seings for the stress score to be green, yellow, orange, or red. If the seings are
too strict or loose for your environment, you can modify them.
vRealize Operations Manager User Guide
76 VMware, Inc.