scenario modelling helps you rationalise your IT infrastructure by automatically optimising the vCPU allocation across all workloads under a host or another segment. When you migrate workloads, you get an option to right-size servers after this migration operation is executed. We recommend that you do as this ensures that the VMs created are sized accordingly based on the capabilities of the target hardware platform.

Different workloads must be optimised and right-sized based on different measures, depending on the behaviour profile of that workload. By default, Capacity Planner uses 95th percentile for CPU right-sizing and the 99th percentile for memory right-sizing. It also allocates enough resources to accommodate that demand while leaving a 20% growth buffer for unexpected peaks.

However, for some VMs, this is not sufficient. There are machines that lie dormant for long periods of time and have very short high CPU spikes. As a result, it may be more appropriate to base the right-sizing of this on CPU peak rather than the 95th percentile.

Also, it may be possible that multiple memory metrics are used to model various aspects of memory demand. That is why Capacity Planner allows you to choose which memory metric to use to right-size.

Select measures

When you right-size, you can select the applicable CPU or memory metric to use and which measure to use. Available measures are:

The percentile figure is the measure defining the amount of time a metric was at a particular value over the course of the baseline used in the scenario. For example, if you pick the 99th percentile for CPU right-sizing, it means that the value used for CPU is the value which the metric has spent 1% of its time at or above over the period of time of the baseline.

When the right-sizing operation is executed, you can check its details in the Operations panel. This includes the measures that are used during right-sizing. For more information, see Operations.


Constrain the right-sizing operation

The following options are available when you want to carry out the right-sizing operation:

To check the results of the right-sizing operation, you can refer to the list of the operations. You can click the information icon to see what options were used in the operation. For example:


You can also check the detailed results of the right-sizing operation. For example, utilisation change:


["Capacity Planner"] ["User Guide", "Configuration"]

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