ESXi can format SCSI-based storage devices as VMFS datastores. VMFS datastores primarily serve as repositories for virtual machines.

With VMFS5, you can have up to 256 VMFS datastores per host, with the maximum size of 64TB. The required minimum size for a VMFS datastore is 1.3GB, however, the recommended minimum size is 2GB.

Note:

Always have only one VMFS datastore for each LUN.

You can store multiple virtual machines on the same VMFS datastore. Each virtual machine, encapsulated in a set of files, occupies a separate single directory. For the operating system inside the virtual machine, VMFS preserves the internal file system semantics, which ensures correct application behavior and data integrity for applications running in virtual machines.

When you run multiple virtual machines, VMFS provides specific locking mechanisms for virtual machine files, so that virtual machines can operate safely in a SAN environment where multiple ESXi hosts share the same VMFS datastore.

In addition to virtual machines, the VMFS datastores can store other files, such as virtual machine templates and ISO images.