ESXi can format SCSI-based storage devices as VMFS datastores. VMFS datastores primarily serve as repositories for virtual machines.
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 the virtual machine files. As a result, the virtual machines can operate safely in a SAN environment where multiple ESXi hosts share the same VMFS datastore.
In addition to the virtual machines, the VMFS datastores can store other files, such as the virtual machine templates and ISO images.