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.