ESXi hosts use storage space on a variety of physical storage systems, including internal and external devices and networked storage.

A host can discover storage devices to which it has access and format them as datastores. Each datastore is a special logical container, analogous to a file system on a logical volume, where the host places virtual disk files and other virtual machine files. Datastores hide specifics of each storage product and provide a uniform model for storing virtual machine files.

Depending on the type of storage you use, datastores can be backed by the following file system formats.

Virtual Machine File System (VMFS) - High-performance file system optimized for storing virtual machines. Your host can deploy a VMFS datastore on any SCSI-based local or networked storage device, including Fibre Channel and iSCSI SAN equipment.

As an alternative to using the VMFS datastore, your virtual machine can have direct access to raw devices and use a mapping file (RDM) as a proxy. See Managing the Virtual Machine File System with vmkfstools.

Network File System (NFS) - File system on a NAS storage device. ESXi supports NFS version 3 over TCP/IP. The host can access a designated NFS volume located on an NFS server, mount the volume, and use it for any storage needs.