HP Capacity Advisor 7.2 User Guide

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You can specify more than one utilization limit for a resource
Using the Utilization Limits Editor, you can add multiple settings for a resource. For example,
you can create multiple different utilization limits for CPU cores by varying percentage and
allowed duration for each limit. Multiple limits for CPU cores could look like this:
◦ Utilization can exceed 90 percent of assigned cores 0 percent of the time
◦ Utilization can exceed 85 percent of assigned cores for a maximum of five minutes
duration
Not specifying a limit allows HP Smart Solver to over-provision systems
To achieve best results with the Smart Solver, it is better to set specific limits, rather than to
depend on the default settings for limits to provide the best fit.
• The time criteria
You can specify the time portion of a utilization limit in either of two ways:
◦ Sustained (consecutive) time limits
◦ Percentage of time limits
Sustained time limits
A sustained limit specifies a limit where the resource cannot exceed that utilization limit for X
consecutive minutes. For example, if X is 20, this means that the resource cannot exceed the
utilization limit for 20 consecutive minutes.
Because the Capacity Advisor collects data samples every five minutes, the time X for the sustained
limit must be a multiple of five minutes; the minimum for X is 0 minutes.
Percentage of time limits
A percentage of time limit specifies that the resource cannot exceed the limit for more than the
designated percent of time, where percent of time is related to the percentile utilization ranges in
the Capacity Advisor data.
Given that there are about 10,000 minutes in a week, 3% of the time is roughly 300 minutes (3%
of 10,000). These 300 minutes total to five hours per week. Below is a table relating percentages
of time to hours per week, which may help you in specifying percent of time utilization limits.
Table 3 Percent of time conversions
Hours/Day
(24–hour day)
Hours/ WeekMinutes/ WeekPercent of Time
.241.68100.81
.483.36201.62
.725.04302.43
1.208.40504.05
2.4016.81008.010
3.6025.21512.015
4.8033.62016.020
6.0042.02520.025
Measuring and analyzing resource utilization 29