A scale-out design
To answer a common question on the influence of Virtual SAN on consolidation ratio and cluster sizing, it only adds a layer of complexity in terms of coupling disk capacity with compute capacity, which otherwise are two mutually exclusive requirements.
By nature of Virtual SAN architecture, it accommodates cluster growth in terms of storage capacity, or compute, or both. In essence, the cluster size needs to be in the VSAN range of minimum to maximum nodes supported, of which only three of the hosts need to contribute to the VSAN datastore. So, in reality, depending on the resource utilization and bottleneck, an administrator can incrementally add disk or compute to scale out.
The number of hosts per cluster and VM to host ratio does not deviate from the traditional design and sizing mechanisms adapted in a virtualized infrastructure. However, there is an additional section in configuration maximums for vSphere 5.x and 6.x guides published by VMware that now includes maximums...
