Overview of iSCSI SAN support

An iSCSI SAN is a storage array network that uses the iSCSI protocol that is built on top of TCP/IP for block level I/O. In an iSCSI SAN the basic unit of data transport is called a protocol data unit (PDU). The PDU is transmitted over a session with one or more TCP/IP connections. Each TCP/IP connection is called a portal and is a member of a portal group.

Data stored in an iSCSI SAN is stored on iSCSI targets. An iSCSI target can be a hardware array or a software iSCSI target node such as Microsoft's iSCSI Software Target. An iSCSI initiator is a server that initiates requests to and receives responses (I/O) from an iSCSI target. An iSCSI session is started when an iSCSI initiator sends a logon request to an iSCSI target. The iSCSI target then responds with a logon response. To complete the login, a series of key=value pairs are negotiated and agreed upon. Logins can be made persistent so that the associated storage is available to the iSCSI initiator following a restart.

Challenge Handshake Authentication Protocol (CHAP) and Internet Protocol Security (IPSec) can be used to make the transmission of commands and data secure in an iSCSI SAN. CHAP can be used with IPSec to ensure an authorized connection between an iSCSI initiator and an iSCSI target.