Typical VM workload and capacity is used by Embotics® vCommander® to calculate the remaining capacity on hosts and clusters, and to determine which resources constrain that capacity. By default, some values have been provided based on performance modeling metrics Embotics® has gathered from our labs and customer environments. CPU, memory and storage are all considered when evaluating capacity.
You can also choose to automatically include new datastores in capacity calculation or not, based on your preference.
Configuring the Global VM Workload
The default values used to calculate the global VM workload are:
- CPU – 0.5 GHz
- Memory – 0.5 GB
- Storage – 8.0 GB
If you have previously profiled the performance of VMs in your environment, or want to proceed with more or less conservative values, you can update the values by following the procedure below.
- Under the Configuration menu, choose System Configuration.
- Switch to the Capacity tab.
- Click Edit.
- Enter values as appropriate and click OK.
Overriding VM Workload for Hosts and Clusters
You can also update the VM workload information for specific hosts and clusters. Doing so overrides the global values, so only the specified values will be considered in any capacity calculation. Overriding the values for a host or cluster has no impact on the global values, or values specified for other hosts or clusters.
When doing so, the averages can be calculated based on the activity over the last 7 days.
- Using the Operational view, right-click the host or cluster for which you want to override the workload values.
- Choose Set VM Workload.
- Select Use Overridden VM Workload.
- Click Calculate Average to have vCommander use the data from the last 7 days to populate the fields. Alternatively, enter values for CPU, Memory and Storage that suit your needs.
- Click OK.
Understanding the Impact on Deployment
The typical workload values are used in conjunction with your choice of how to select deployment targets, using either their average capacity or peak capacity.
For example, on the target page of the wizard shown above, Embotics vCommander displays the capacity remaining and constraining resource based on the average capacity of the VMs currently residing on the selected host.
So, the average CPU, memory, and storage utilization is used to figure out how much of the host’s resources are already consumed. The remaining resources are then compared to the typical VM workload numbers, set globally or overridden for the host, and the remaining capacity is presented.
In the example above, using average values estimates that there is enough room left for 6 more VMs. Using peak values reduces that to enough room for 5 VMs. In both cases, the resource constraining the estimates most is CPU.