If you are an ESX/ESXi administrator who plans to set up ESX/ESXi hosts to work with SANs, you must have a working knowledge of SAN concepts. You can find information about SAN in print and on the Internet.

iSCSI SANs use Ethernet connections between computer systems, or host servers, and high performance storage subsystems. The SAN components include iSCSI host bus adapters (HBAs) or Network Interface Cards (NICs) in the host servers, switches and routers that transport the storage traffic, cables, storage processors (SPs), and storage disk systems.

iSCSI SAN uses a client-server architecture. The client, called iSCSI initiator, operates on your host. It initiates iSCSI sessions by issuing SCSI commands and transmitting them, encapsulated into iSCSI protocol, to a server. The server is known as an iSCSI target. The iSCSI target represents a physical storage system on the network. It can also be provided by a virtual iSCSI SAN, for example, an iSCSI target emulator running in a virtual machine. The iSCSI target responds to the initiator's commands by transmitting required iSCSI data.