About iSCSI

iSCSI is a new networking - data storage protocol that combines SCSI data blocks with Ethernet IP packets.  SCSI commands are encoded in to Ethernet packets and then sent over Ethernet networks.  When they reach their destination these packets are separated out using the off-load engine into Ethernet and SCSI commands and the data is then sent to the relevant device.

As iSCSI uses existing Ethernet switches, cables, routers the deployment costs are much lower than if you were to design a Fibre Channel SAN.  Operating systems see iSCSI-connected devices as SCSI devices and are unaware that the SCSI device connected to the network resides across the room or across town.

iSCSI SAN

An iSCSI SAN will cost considerably less the reasons for this are:

  Many manufacturers will be supplying Gigabit Ethernet cards with built-in iSCSI offload engines as standard

  No new investment in network architectures as an existing Gigabit network will suffice

  No new software as the device on an iSCSI network look like SCSI devices

  iSCSI is fully supported by Microsoft, Cisco etc.