Proware EP-3164D-GAS3, User Manual

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iSCSI GbE to SAS/SATA II RAID Subsystem
34 User Manual
3.4 iSCSI Introduction
iSCSI (Internet SCSI) is a protocol which encapsulates SCSI (Small Computer System
Interface) commands and data in TCP/IP packets for linking storage devices with
servers over common IP infrastructures. iSCSI provides high performance SANs over
standard IP networks like LAN, WAN or the Internet.
IP SANs are true SANs (Storage Area Networks) which allow few of servers to attach to
an infinite number of storage volumes by using iSCSI over TCP/IP networks. IP SANs
can scale the storage capacity with any type and brand of storage system. In addition,
using any type of network (Ethernet, Fast Ethernet, Gigabit Ethernet) and combining
operating systems (Microsoft Windows, Linux, Solaris, …etc.) within the SAN network.
IP-SANs also include mechanisms for security, data replication, multi-path and high
availability.
Storage protocol, such as iSCSI, has “two ends” in the connection. These ends are the
initiator and the target. In iSCSI we call them iSCSI initiator and iSCSI target. The
iSCSI initiator requests or initiates any iSCSI communication. It requests all SCSI
operations like read or write. An initiator is usually located on the host/server side
(either an iSCSI HBA or iSCSI SW initiator).
The iSCSI target is the storage device itself or an appliance which controls and serves
volumes or virtual volumes. The target is the device which performs SCSI commands
or bridges it to an attached storage device. iSCSI targets can be disks, tapes, RAID
arrays, tape libraries, and etc.
iSCSI device 1
(target)
Host 1
(initiator)
NIC
IP SAN
Host 2
(initiator)
iSCSI
HBA
iSCSI device 2
(target)