This measure is not available for the ‘Total’ descriptor.

By comparing the values reported by the Disk files, Snapshot files, Swap files, and Other VM files measures, you can accurately identify the type of files that are occupying too much space on a datastore.

If SIOC is active, the value of this measure will be 100%. If it is not active, the value of this measure will be 0.

Measure Value	Description
VMFS	VMFS (Virtual Machine File system) is a high-performance cluster file system optimized for virtual machines. While conventional file systems allow only one server to have read-write access to the same file system at a given time, VMFS leverages shared storage to allow multiple VMware vSphere hosts to read and write to the same storage concurrently.
NFS	This is a file system on a NAS storage device. The vSphere host can access a designated NFS volume located on an NFS server, mount the volume, and use it for any storage needs.
NFSV41	NFS v4.1 introduces better performance and availability through load balancing and multipathing. Another major enhancement with NFS v4.1 is the security aspect. With this version, Kerberos and thus non-root user authentication are both supported.
CIFS	CIFS is the standard way that computer users share files across corporate intranets and the Internet.
VFAT	Virtual File Allocation Table (VFAT) handles long file names, which otherwise could not be handled by the original file allocation table (FAT) programming. A file allocation table is the means by which the operating system keeps track of where the pieces of a file are stored on a hard disk. Since the original FAT assumed file names were limited to a length of eight characters, a program extension was needed to handle the longer names. Microsoft refers to this extension as a driver. The VFAT extension runs in protected mode, uses 32-bit code, and uses VCACHE for disk cache.
VSAN	Virtual SAN virtualizes local physical storage resources of vSphere hosts and turns them into pools of storage that can be carved up and assigned to virtual machines and applications according to their quality of service requirements.
VFFS	VFFS (Virtual Flash File System) is a derivative of VMFS, which is optimized for SSDs and is used to group the physical SSDs into a single caching resource pool. It is a non-persistent resource and, therefore, virtual machines cannot be stored in it. A VFFS resource pool can be created from mixed resources. All devices types are treated the same and no distinction is made between SAS, SATA, PCI express connectivity.

The numeric values that correspond to each of the Measure Values listed above are as follows:

By default, this measure reports the Measure Values listed in the table above. In the graph of this measure however, the file system type of the datastore is represented using the corresponding numeric equivalents only.