Rightsizing in VMware Aria Operations refers to the process of adjusting the resource allocations of virtual machines (VMs) to match their actual workload requirements. It involves optimizing the allocation of CPU, memory, storage, and other resources to ensure that VMs are neither overprovisioned (allocating more resources than necessary) nor underutilized (allocating fewer resources than needed). The goal of rightsizing is to achieve efficient resource utilization, improve performance, and potentially reduce costs Use the Rightsize page to alter the number of CPUs and amount of memory in oversized and undersized virtual machines.

Where You Find Rightsizing

Select Rightsize under Capacity in the left pane. Then, select a data center.

How Rightsizing Works

The Capacity Optimization, Reclaim, and Rightsizing features are tightly integrated functions that allows you to assess workload status and resource usage in data centers across your environment. You can determine time remaining until CPU, memory, or storage resources run out, and realize cost savings when underutilized VMs can be reclaimed and deployed where needed. With this function, you can change CPU size and memory values for oversized and undersized virtual machines to achieve optimum system performance.

When you open the page, graphical representations of all the data centers and custom data centers in your environment appear. By default, they are shown in order of time remaining, beginning from the upper left, where the most constrained data centers appear. To identify possible oversized and undersized VMs in a data center, click its graphic. The area following refreshes to display details about the selected data center.

"Oversized VMs" displays the number of VMs determined to be oversized based on policies previously set. A chart details suggested reductions in the overall number of CPUs and GBs of memory and shows the percentage of total resources the reductions represent. Similarly, "Undersized VMs" indicates the number of VMs considered to be undersized, with a chart listing suggested increases in CPU and memory.

The table at the bottom of the page provides important information about the VMs. Table headings are Oversized VMs and Undersized VMs. VMs under each heading are grouped by cluster. Click the chevron to the left of a cluster name to list all the oversized or undersized VMs, respectively, in that cluster. You can check the box next to one or more VM names and click the EXCLUDE VM(S) button to prevent those VMs from being included in a resizing action. You can also select individual VMs to resize before clicking the RESIZE VM(S) button.

Run a Rightsize Action on Oversized VMs

Run the action as follows:

  1. Click the Oversized VM tabs.
  2. Select the VMs you want to exclude from the action, if any and click EXCLUDE VM(S). In the confirmation dialog box, click EXCLUDE VM(S).
  3. Select the VMs you want to include in the resizing action, or click the checkbox next to VM Name to include all VMs.
  4. Click RESIZE VM(S). The Resize VM(S) workspace appears. The table displays suggested reductions for vCPU and memory. Click the edit icons to accomplish to changes you wish.
    Note: Operational Actions must be activated in the vCenter cloud adapter instance.
  5. Select the checkbox at the bottom of the screen to indicate your understanding that, because workloads must restart to accommodate resizing, some work may be interrupted.

Run a Rightsize Action on Undersized VMs

Run the action as follows:

  1. In the table headings, Select Undersized VMs.
  2. Select the VMs you want to exclude from the action, if any and click EXCLUDE VM(S). In the confirmation dialog box, click EXCLUDE VM(S).
  3. Select the VMs you want to include in the resizing action, or click the checkbox next to VM Name to include all VMs.
  4. Click RESIZE VM(S). The Resize VM(S) workspace appears. The table displays suggested increases for vCPU and memory. Click the edit icons to accomplish to changes you wish.
  5. Select the checkbox at the bottom of the screen to indicate your understanding that, because workloads must restart to accommodate resizing, some work may be interrupted.
Table 1. Rightsize Options
Option Description

Select a data center.

Select a data center from the carousel across the top of the page. All data refreshes with information for the selected object.

ALL DATACENTERS | X Toggle: click ALL DATACENTERS on the upper right when you want to switch the view to a filtered list of all data centers. Click X to return to a carousel view of data centers.
View: Filter results to include data centers, custom data centers, or both. Option appears when you select ALL DATACENTERS on the upper right.
Group BY: Filter results by criticality (least time remaining data centers/custom data centers listed first) or by the vCenter Server to which each data center belongs. Option appears when you select ALL DATACENTERS on the upper right.
Sort by:

Options (Options appear when you select ALL DATACENTERS on the upper right):

  • Alarm clock graphic - list data centers/custom data centers by time remaining.
  • Dollar sign - list data centers/custom data centers by potential cost savings.
  • Scales graphic - list data centers/custom data centers by level of optimization.
Select data center or ADD NEW CUSTOM DATACENTER.

Options (Options appear when you select ALL DATACENTERS on the upper right):

  • Select a data center from the carousel across the top of the page. All data refreshes with information for the selected object.
  • Select ADD NEW CUSTOM DATACENTER to display a dialog box that allows you to define a custom data center.
Oversized VMs display

Displays the number of VMs identified as oversized, with suggested reductions for vCPU and memory size.

Undersized VMs display

Displays the number of VMs identified as undersized, with suggested increases for vCPU and memory size.

Table of Oversized and Undersized VMs

Tabular representation of the Oversized and Undersized VMs in the selected data center.

Click one of the headings - Oversized VMs or Undersized VMs - to refresh the table with data for that heading. The table lists the relevant VMs. To see the VMs hosted in a given cluster, click the chevron to the left of the cluster name.

Click the check box next to the VMs you want to act on, or click the check box next to the column heading VM Name to act on all the VMs.

Click the expand icon next to a VM to see an explanation of how VMware Aria Operations computes the recommended size. The visual representation shows you the historical utilization pattern, the projection and the recommendation for rightsizing. You can change the graphical representation to show the history from one month to 12 months.
Note: The rightsizing recommendation is influenced by the risk level that you set in the policy. You can modify the risk level in the policy to change the recommendation.

Once you select a VM or VMs, the dimmed options above the table become visible, as follows.

Exclude VM(s): the selected VMs are excluded from your subsequent action. Excluding VMs from a reclamation action can reduce the potential cost savings.

For Oversized VMs:
  • SCHEDULE ACTION: Displays a dialog box enabling you to schedule one or more resize actions for oversized VMs. Expand the cluster name displayed in the table and select one or more VMs. Then, from the SCHEDULE ACTION drop down menu, select an action to be performed later. In the dialog box, you configure the schedule for the job. Scheduled jobs can be managed in Automation Central.
  • RESIZE VM(s): The system displays a dialog box with suggestions for reducing vCPUs and memory. Click the edit icons to change resource size.
  • EXCLUDE VM(s): Excludes the selected VMs.
  • EXPORT ALL: Exports the list of powered off VMs into a CSV file.
For Undersized VMs:
  • SCHEDULE ACTION: Displays a dialog box enabling you to resize VM actions for undersized VMs. Expand the cluster name displayed in the table and select one or more VMs. Then, from the SCHEDULE ACTION drop down menu, select an action to be performed later. In the dialog box, you configure the schedule for the job. Scheduled jobs can be managed in Automation Central.
  • RESIZE VM(s): The system displays a dialog box with suggestions for increasing vCPUs and memory. Click the edit icons to change resource size.
  • EXCLUDE VM(s): Excludes the selected VMs.
  • EXPORT ALL: Exports the list of powered off VMs into a CSV file.

SHOW|HIDE EXCLUDED VMS: toggle displays or hides the list of VMs you previously excluded.

INCLUDE VM(s): include the selected VMs in the actionable list.