Virtual SAN refers to a software-defined storage technology from VMware that helps enterprises pool together their different storage capabilities and instantly give access provisions to the virtual machine storage space via simple policies that are managed and driven by a virtual machine.
Virtual SAN virtualizes the local physical storage media of the ESXi hosts and proceeds to turn them into expansive pools of storage spaces that can be individually carved and get assigned to more than one Virtual machine and applications in accordance to the quality of service required by those machines and applications.
You can easily activate The Virtual SAN after creating host clusters or enabling Virtual SAN on The existing clusters. So when fully enabled, Virtual SAN gets The privilege of aggregating all the local storage disks that are available on all The hosts into one datastore which ends up being shared by all connected hosts. You can choose to come back later and expand the established datastore by simply adding extra hosts or storage devices to the cluster.
The hosts in a Virtual SAN group or cluster don’t need to be identical. Hosts without local disks can still participate and run their standalone Virtual machines on a Virtual SAN’s datastore
If a given host contributes its own local storage to a Virtual SAN datastore, such as host will be required to provide at least 1 HDD and another 1 SSD, also known as a data disk. Eventually, the disks on a contributing host are made to form one disk group. Every disk group is required to include 1 SSD and at least 1 or more data disks. In this arrangement, the disk group is tasked with using The SSD disk for competing write buffering and read caching, while its data disks tasked with offering persistent storage solutions. It is possible for a host to have more than 1 disk group with host 1 containing one disk group and host 3 having two disk groups while belonging to the same pool.
Virtual SAN and The accompanying Virtual Machine storage Policy
When enabled, The Virtual SAN tends to works together with the storage policies of Virtual machines. You use the set storage policies to clearly define The Virtual machine storage requirements including availability and performance in a profile-like form. The policy requirements tends to be forwarded to the layer of Virtual SAN once a Virtual disk has been created.