This topic summarizes characteristics that apply to Virtual SAN, as well as its clusters and datastores.

When you work with Virtual SAN, consider the following:
  • Virtual SAN is implemented directly in the ESXi hypervisor.
  • Virtual SAN supports VMware features that require shared storage, such as HA, vMotion, and DRS. For example, if a host becomes overloaded, DRS can migrate virtual machines to other hosts in the cluster.
  • Virtual SAN integrates with vSphere data management features traditionally used with VMFS and NFS storage. These features include snapshots, linked clones, vSphere Replication, and vSphere APIs for Data Protection.
  • Virtual SAN works with Virtual Machine Storage Policies to support a virtual machine-centric storage approach.

Limitations of Virtual SAN

  • Virtual SAN does not support multiple Virtual SAN clusters for each host.
  • Virtual SAN does not support virtual machines with large capacity virtual disks, or disks greater than 2TB.
  • Virtual SAN supports only SATA, SAS HDD, and PCIe storage. You cannot use storage attached through USB, Fibre Channel, or iSCSI.
  • Virtual SAN does not support such features as Fault Tolerance, vSphere DPM, and Storage I/O Control.
  • Virtual SAN does not support SE Sparse disks.
  • Virtual SAN does not support SCSI reservations.
  • Virtual SAN does not support RDM, VMFS, diagnostic partition, and other disk access features.

Characteristics of a Virtual SAN Cluster

  • Virtual SAN clusters can include hosts with storage disks, or without. The minimum requirement is three hosts with storage disks.
  • If a host contributes storage devices, it must have one SSD and at least one HDD device.
  • Only local or direct-attached storage devices can participate in a Virtual SAN cluster. Virtual SAN does not use any other storage, such as SAN or NAS, attached to cluster.
  • Virtual SAN takes up entire disks, including SSD and data disks, and does not share disks with other features.
  • You can have multiple Virtual SAN clusters for each vCenter Server instance.

Characteristics of a Virtual SAN Datastore

  • Virtual SAN creates a single Virtual SAN datastore accessible to all hosts in the cluster, whether or not they have disks. All hosts can also mount any other datastores, VMFS or NFS.
  • If you have multiple Virtual SAN clusters for each vCenter Server, each cluster provides a Virtual SAN datastore. You can use Storage vMotion to move virtual machines between the Virtual SAN datastores.
  • Only HDD disks contribute to the capacity of the datastore. The capacity of SSDs is not counted as part of the datastore.
  • In automatic mode, a Virtual SAN datastore dynamically grows when you add hosts to a Virtual SAN cluster, or disks to any cluster member.