Each component of the solution architecture scales independently, depending on the required number of supported users. You can add appliance nodes at any time to expand the vSAN SDS pool in a modular fashion. The limits of the hypervisor at 64 nodes per block restricts the scaling limit for vSAN.
The boundary for a Horizon block is the vCenter. The number of VMs a vCenter can host depends on the type of Horizon 8 VMs being used. The recommended limit of virtual machines per vCenter is 20,000 full-clone or instant-clone VMs.
Sizing recommendations change over time as updates are released and qualifications are performed. See the VMware Configuration Maximums website for the latest recommendations.
This Dell Validated Design for VDI uses instant clones, as shown in the following figures. VMware recommends a limit of 5,000 instant-clone VMs per block. With these limits in mind, 20 compute nodes with 200 task-user VMs per node would reach the maximum number of VMs for the block.
The following figure shows a 5,000-user Horizon block:
