Scalability does not have a standard metric used across the industry. Generally, performance or load testing can be done on a system to determine how flexible it can handle changes in demand.

For example, performance testing can be done to measure how long a system takes to add more resources and meet peak demand. A system that only takes one minute to add more resources is more scalable than a system that takes an hour to perform the same action.

Designing for Scale

There are several options for scalability of a VMware Cloud SDDC. An organization may begin with scaling up a vSphere cluster by adding hosts to meet an increase in demand. Organizations can enable automatic resource allocations such as Elastic Distributed Resource Scheduler (eDRS) which is available in a VMware Cloud on AWS SDDC. If an automated resource allocation service is not available in a VMware Cloud SDDC, the process of adding a host can be automated by leveraging the VMware Cloud SDDC APIs.

If scaling up a vSphere cluster reaches the VMware Cloud configuration maximums or does not fulfill the business needs, the next option is to scale out by creating additional vSphere clusters within the same VMware Cloud SDDC. It is important to determine when a new vSphere cluster should be created to plan for day two operations and manage the growth of an environment.

Depending on the business needs and the estimated growth, an organization may choose to create multiple VMware Cloud SDDCs instead of scaling up a single SDDC. It is essential to identify any workloads that must communicate with each other spanning several VMware Cloud SDDCs to design the network connectivity between these environments appropriately.

In addition to the virtual infrastructure, the VMware management Virtual Machines should also be considered when designing for scalability. Typically, the management Virtual Machines, such as the vCenter Server and NSX managers, will be deployed with a pre-defined set of compute and storage resources. Based on the workload requirements and expected utilization collected during the initial assessment, the VMware management Virtual Machines may need to be resized if this capability is available within a VMware Cloud SDDC.

Overall, a VMware Cloud environment should be designed to be repeatable. A modular design makes an environment easier to replicate or expand across different regions to meet fast-growing demand. An organization should plan how their VMware Cloud SDDC will expand when designing the first VMware Cloud SDDC to expedite the deployment of a new VMware Cloud SDDC as well as to simplify cloud management and day two operations in the future.


VMware Cloud Sizer can be used to size the VMware Cloud based SDDC with data collected during the initial assessment. Configuration maximums can also be referenced to ensure scalability of the VMware Cloud SDDC.