6.0.1

n
“Conguring VMFS Pointer Block Cache,” on page 179
Understanding VMFS Datastores
To store virtual disks, ESXi uses datastores, which are logical containers that hide specics of physical
storage from virtual machines and provide a uniform model for storing virtual machine les. Datastores
that you deploy on block storage devices use the vSphere VMFS format, a special high-performance le
system format that is optimized for storing virtual machines.
Several versions of the VMFS le system have been released since its introduction. The following table
shows host-to-VMFS version relationships.
Table 16‑1. Host access to VMFS version
VMFS ESX/ESXi 3.x host ESX/ESXi 4.x host ESXi 5.x host ESXi 6.x host
VMFS2 RO RO N N
VMFS3 RW RW RW RW
N You can continue
to use existing VMFS3
datastores, but you
cannot create new ones.
If you have existing
VMFS3 datastores,
upgrade them to VMFS5.
VMFS5 N N RW RW
n
RW: Complete read and write support. You can create and power on virtual machines.
n
RO: Read only support. You cannot create or power on virtual machines.
n
N: No access. ESXi 5.x and later hosts do not support VMFS2. If your datastore was formaed with
VMFS2, rst upgrade the datastore to VMFS3 using legacy hosts.
Use the vSphere Web Client to set up a VMFS datastore in advance on a block-based storage device that
your ESXi host discovers. A VMFS datastore can be extended to span several physical storage extents,
including SAN LUNs and local storage. This feature allows you to pool storage and gives you exibility in
creating the datastore necessary for your virtual machines.
N Pooling ATS-capable hardware creates a spanned VMFS datastore that can use ATS-only locking
mechanism. If any device is not ATS-capable, the datastore cannot be ATS-only, but uses ATS+SCSI locking.
You can increase the capacity of a datastore while virtual machines are running on the datastore. This ability
lets you add new space to your VMFS datastores as your virtual machine requires it. VMFS is designed for
concurrent access from multiple physical machines and enforces the appropriate access controls on virtual
machine les.
Characteristics of VMFS5 Datastores
VMFS5 provides many improvements in scalability and performance.
VMFS5 has the following Characteristics:
n
Greater than 2TB storage devices for each VMFS5 extent.
n
Support of virtual machines with large capacity virtual disks, or disks greater than 2TB.
n
Increased resource limits such as le descriptors.
n
Standard 1MB le system block size with support of 2TB virtual disks.
n
Greater than 2TB disk size for RDMs.
vSphere Storage
146 VMware, Inc.