Networked storage consists of external storage systems that your ESX host uses to store virtual machine files remotely. Typically, the host accesses these systems over a high-speed storage network.

Networked storage devices are shared. Datastores on networked storage devices can be accessed by multiple hosts concurrently. ESX supports the following networked storage technologies.


Accessing the same storage through different transport protocols, such as iSCSI and Fibre Channel, at the same time is not supported.

Fibre Channel (FC)

Stores virtual machine files remotely on an FC storage area network (SAN). FC SAN is a specialized high-speed network that connects your hosts to high-performance storage devices. The network uses Fibre Channel protocol to transport SCSI traffic from virtual machines to the FC SAN devices.

To connect to the FC SAN, your host should be equipped with Fibre Channel host bus adapters (HBAs). Unless you use Fibre Channel direct connect storage, you need Fibre Channel switches to route storage traffic. If your host contains FCoE (Fibre Channel over Ethernet) HBAs, you can connect to your shared Fibre Channel devices using an IP network.

Internet SCSI (iSCSI)

Stores virtual machine files on remote iSCSI storage devices. iSCSI packages SCSI storage traffic into the TCP/IP protocol so that it can travel through standard TCP/IP networks instead of the specialized FC network. With an iSCSI connection, your host serves as the initiator that communicates with a target, located in remote iSCSI storage systems.

ESX offers the following types of iSCSI connections:

Hardware iSCSI

Your host connects to storage through a third-party adapter capable of offloading the iSCSI and network processing.

Software iSCSI

Your host uses a software-based iSCSI initiator in the VMkernel to connect to storage. With this type of iSCSI connection, your host needs only a standard network adapter for network connectivity.

Network-attached Storage (NAS)

Stores virtual machine files on remote file servers accessed over a standard TCP/IP network. The NFS client built into ESX uses Network File System (NFS) protocol version 3 to communicate with the NAS/NFS servers. For network connectivity, the host requires a standard network adapter.

Shared Serial Attached SCSI (SAS)

Stores virtual machines on direct-attached SAS storage systems that offer shared access to multiple hosts. This type of access permits multiple hosts to access the same VMFS datastore on a LUN.