VMware vSAN Storage design includes conceptual design, logical design, network design, vSphere cluster and disk group design, and policy design.

In a cluster that is managed by vCenter Server, you can manage software-defined storage resources similar to compute resources. Instead of CPU or memory reservations, limits, and shares, you can define storage policies and assign them to VMs. The policies specify the characteristics of the storage and can be changed as the business requirements change.

vSAN Disk Groups

Disk group sizing is an important factor during the volume design. If more ESXi hosts are available in a cluster, more failures are tolerated in the cluster. This capability adds cost because additional hardware is required for the disk groups.

More available disk groups can increase the recoverability of vSAN during a failure. When deciding on the number of disk groups per ESXi host, consider these points:

  • Amount of available space on the vSAN datastore

  • Number of failures that can be tolerated in the cluster

The optimal number of disk groups is a balance between the hardware and space requirements for the vSAN datastore. More disk groups increase space and provide high availability. However, adding disk groups can be cost-prohibitive.

Table 1. Recommended Shared Storage Design

Design Decision

Design Justification

Design Implication

Configure vSAN with a minimum of one disk group per ESXi host.

A single disk group provides the required performance and usable space for the datastore.

Losing the caching tier disk in an ESXi host takes the disk group offline.

Using two or more disk groups can increase availability and performance.


This design uses vSAN. Any supported storage solution that meets the characteristics of this storage design can be used. For best practices, see the vendor documentation.