You size the compute resources of the ESXi hosts in a VI workload domain in VMware Cloud Foundation according to the requirements of the customer workloads and NSX Edge nodes.

This design applies the shared edge and compute architecture to the vSphere clusters of a VI workload domain. In this architecture, the NSX Edge nodes and customer workloads share the resources of the same cluster, using resource pools to allocate CPU and memory to the NSX Edge appliances with high priority and to customer workloads according to their SLA. See High Availability Design for the NSX Edge Nodes for a Virtual Infrastructure Workload Domain.

ESXi Server Hardware

The configuration and assembly process for each system should be standardized, with all components installed in the same manner on each ESXi host. Because standardization of the physical configuration of the ESXi hosts removes variability, the infrastructure is easily managed and supported. ESXi hosts should be deployed with identical configuration across all cluster members, including storage and networking configurations. For example, consistent PCIe card installation, especially for network controllers, is essential for accurate mapping of physical network controllers to virtual network resources. You ensure an even distribution of resources to virtual machines across the ESXi hosts in a cluster by standardizing components within each physical server.
  • An average-size virtual machine has two virtual CPUs with 4 GB of RAM.

  • A typical spec 2U ESXi host can run 60 average-size virtual machines.

In VMware Cloud Foundation, the principal storage system for a VI workload domain can be VMware vSphere VMFS on FC, vSphere Virtual Volumes (vVols), NFS or VMware vSAN. See Storage Management in the VMware Cloud Foundation Administration Guide and Shared Storage Design for a Virtual Infrastructure Workload Domain.
Table 1. Design Decisions on ESXi Server Hardware

Decision ID

Design Decision

Design Justification

Design Implication

VCF-WLD-ESX-CFG-001

For vSAN principal storage, use vSAN ReadyNodes for each ESXi host in the cluster in the VI workload domain.

Your VI workload domain is fully compatible with vSAN at deployment.

For information about the models of physical servers that are vSAN-ready, see vSAN Compatibility Guide for vSAN ReadyNodes.

Hardware choices might be limited.

If you plan to use a server configuration that is not a vSAN ReadyNode, your CPU, disks and I/O modules must be listed on the VMware Compatibility Guide under CPU Series and vSAN Compatibility List aligned to the ESXi version specified in VMware Cloud Foundation 4.3 Release Notes.

VCF-WLD-ESX-CFG-002

Allocate hosts with uniform configuration across the cluster in the VI workload domain.

A balanced cluster has these advantages:

  • Predictable performance even during hardware failures

  • Minimal impact of resync or rebuild operations on performance

You must apply vendor sourcing, budgeting, and procurement considerations for uniform server nodes, on a per cluster basis.

ESXi Host Memory

When sizing memory for the ESXi hosts in the VI workload domain, consider certain requirements.

  • Requirements for the customer workloads that are running in the cluster

    When sizing memory for the hosts in a cluster, to reserve the resources of one host for failover or maintenance, set the admission control setting to N+1, which reserves the resources of one host for failover or maintenance.

  • Number of vSAN disk groups and disks on an ESXi host if you plan to use vSAN principal storage in the VI workload domain

    To support the maximum number of disk groups, you must provide 32 GB of RAM. For more information about disk groups, including design and sizing guidance, see Administering VMware vSAN from the vSphere documentation and Sizing vSAN Resources for a Virtual Infrastructure Workload Domain.

Table 2. Design Decisions on the ESXi Memory Size

Decision ID

Design Decision

Design Justification

Design Implication

VCF-WLD-ESX-CFG-003

In a cluster in the VI workload domain, install each ESXi host with a minimum of 256 GB RAM.

Each of the two large-size NSX Edge appliances in this vSphere cluster of the VI workload domain requires 64 GB RAM.

The remaining RAM is available for customer workloads.

In a four-node cluster, only 768 GB is available for use because the host redundancy in vSphere HA is configured to N+1.