The VM Rightsizing dashboard helps you adjust the VM size for optimal performance and capacity. It covers both undersized and oversized scenarios. This dashboard is designed for the Capacity and the Operations teams, as rightsizing VMs benefit the day-to-day performance.

Design Considerations

The VM Rightsizing dashboard helps you visualize information differently by providing choices for customization. It focuses on a summary that helps discussions with senior management. The reclamation size is grouped into buckets so that you can focus on the largest reclamation opportunities first.

How to Use the Dashboard

Select a data center from the Datacenters widget.
  • The cluster capacity remaining is displayed to give a better context. Focus on reclaiming the cluster that is low on capacity remaining, and on upsizing the cluster with a high capacity remaining.
Once you select a data center from the Datacenters widget, all the remaining widgets automatically display the information of the selected data center.
  • There are two widgets for upsizing recommendation, one for CPU and one for Memory.
  • There are two widgets for downsizing recommendation, one for CPU and one for Memory.
  • The business processes for oversized and undersized VMs are different, as one requires the affected VM to be shut down and the Owner to return the resources. To upsize, you must add incrementally. To downsize, you must remove in one change window as the effort to reduce is the same and there will be only one downtime.

Points to Note

  • The metrics used are Summary|Oversized|Virtual CPUs and Summary|Undersized|Virtual CPUs. It stores the capacity engine calculation on the recommended number of vCPUs that must be removed or added.
  • When you change the VM configuration, the application setting might have to change. This is especially on applications that manage its memory (for example, database and JVM), and schedules the fixed number of threats.
  • Avoid reducing vCPUs from greater than 1 to 1 for Windows. The SMP kernel is activated during the first installation and the performance can degrade on a uni-processor machine.
  • You can enable Hot Add on VM, but take note of the impact on NUMA.
  • For more details on rightsizing, see Rightsizing VMs with vRealize Operations.