A VMware Cloud on AWS SDDC virtualizes networking, storage, and compute resources. Understanding the needs of your SDDC workloads can help you design and deploy an SDDC that meets those needs in a scalable, cost-effective way.

Matching SDDC Resources to Workload Needs

SDDC compute (CPU), memory, and storage resources are provided by the host and storage types you choose when you create the SDDC There are two separate systems that run in an SDDC to manage resources and ensure workloads have sufficient capacity available to support their operation:
vSphere Distributed Resource Scheduler (DRS)
DRS can migrate workloads between hosts in a cluster to help ensure that all available host resources are being used to meet workload requirements. DRS also makes use of vSphere HA Admission Control to ensure that sufficient capacity is reserved so that in case of a host failure, all resource reservations applied to powered-on VMs are met. It acts as a gatekeeper and will prevent a VM from powering on if the cluster does not have sufficient resources to satisfy those reservations in such a scenario.
VMware Cloud on AWS Elastic DRS
Elastic DRS is a feature, unique to VMware Cloud on AWS, that monitors total cluster utilization and, using customer-defined policies, can add or remove hosts to optimize the cluster performance/cost equation. VMware Cloud on AWS allows hosts to be added or removed on demand. Any hosts that get added by EDRS are be billed at on-demand rates until they are removed unless a matching subscription is available.

One of the best places to start figuring out the SDDC resources needed by your workloads is the VMware Cloud Sizer. This complimentary VMware Cloud service estimates the resources required to run various predefined workloads given a specified number of virtual CPUs (cores). Read the VMware Cloud Sizer Feature Brief to learn more.

Storage

An SDDC can use vSAN or external NFS storage. The host and storage types you choose when you create the SDDC apply to SDDC Cluster-1, which supports SDDC management appliances. When you add clusters to the SDDC, you can use other host types if you want. For more information, see VMC on AWS Host Types. The VMware Cloud Tech Zone article VMware Cloud on AWS: Storage Architectureexplains our storage architecture and available storage types. And the VMware Cloud Tech Zone Designlets VMware Cloud on AWS Management Cluster Planning and VMware Cloud on AWS: Stretched Clusters provide an in-depth discussion of SDDC host and cluster configuration options.

Compute and Memory

SDDC compute and memory capacity is determined by host count and host type. VMware Cloud on AWS provides host types suited to various resource consumption profiles: storage-optimized, compute-optimized, and a balance of the two. In addition to the list in VMC on AWS Host Types, there's also a Host Types Feature Brief that provides a more detailed look at host types and their capabilities. An understanding of the compute (CPU) and memory requirements of your workload VMs can help you choose the host type for your initial cluster, and for any additional clusters you add to your SDDC. You can find CPU, memory, and storage details for all supported VMware Cloud on AWS host types in VMware Configuration Maximums.