HP Virtualization Manager and HP Capacity Advisor: an introduction

Editing of the baseline is performed using the Capacity Advisor baseline editor. Unless
you made modifications, Capacity Advisor derives the baseline directly from historic infor-
mation. In some cases the baseline does not require modification. However, most of the time
workloads are event driven or cyclical in nature and adjusting the baseline results in a much
more accurate and reliable model for capacity-planning purposes. For example, a payroll
workload that runs on a biweekly basis requires editing of the baseline in order to accurately
plan for the workload and its requirements in the future. Consider a situation where a pay-
roll workload is being consolidated with a workload that runs at the end of each month.
Using the baseline editor for each of these workloads to specify the exact nature of the work-
load makes it readily apparent that consolidating these workloads might not be feasible be-
cause some days payroll is processed on the same day as the month-end processing. This
simple example illustrates why it is important to create an accurate baseline. If the baseline
for the payroll workload does not accurately reflect the workload, the capacity-planning sce-
nario evaluating this consolidation might overlook the problematic times where the peaks for
the two workloads are aligned.
The final aspect of editing a workload’s forecast is accounting for expected events in the work-
load’s future. Events such as obsolescing a workload or doubling a workload’s user base due to
a merger can be specified as part of the forecasting process. These events further ensure that the
capacity-planning activities performed on a workload are reliable and properly account for
known events in a workload’s future.
Once the workloads’ historic profiles and forecasts have been customized, the next step is cre-
ating a Capacity Advisor scenario. This process allows many workloads to be evaluated as a group.
A scenario is a set of systems and workloads combined together for capacity-planning purposes.
Using the workload forecasts, what-if scenarios can be evaluated to determine if workload mi-
grations, consolidations, or introductions will be successful. Hypothetical systems and workloads
can also be defined within a scenario to provide what-if planning facilities. The hypothetical sys-
tems can be used to assist in answering questions such as “Will these workloads perform accept-
ably on the system I’m purchasing?” Additionally, scenarios can be used to evaluate the effects of
moving a workload from one system to another. Essentially, capacity-planning scenarios provide
a test-bed for performing analysis using both real and hypothetical systems and workloads. These
scenarios are reliable because they are based on historic workload utilization data. The historic data
is then used to create a forecast and baseline for the workload. The Capacity Advisor product al-
lows capacity planners to effectively and accurately plan for changes in the datacenter.
A Reason for Capacity Planning
Before diving in to the Capacity Advisor example scenario, one of the many reasons for capac-
ity planning is illustrated using an experiment that was performed using data from production
workloads in HP’s internal IT department. In this experiment, the data for two production work-
loads was collected. The data was then used to determine whether consolidating the two work-
loads would result in reduced hardware requirements. Of course, reducing the number of required
CPUs results in a reduction in both hardware costs and software licensing costs.
chapter 18 Capacity Advisor
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