Iscsi Initiators And Targets - IBM System Storage DS3500 Introduction And Implementation Manual

Draft Document for Review March 28, 2011 12:24 pm

1.3.1 iSCSI initiators and targets

iSCSI uses the concept of initiators and targets, as shown in Figure 1-6.
Figure 1-6 iSCSI components
The protocol allows clients (called initiators) to send SCSI commands (CDBs) to SCSI
storage devices (targets) on remote servers.
An initiator functions as an iSCSI client. An initiator typically serves the same purpose to a
computer as a SCSI bus adapter would, except that instead of physically cabling SCSI
devices (like hard drives and tape changers), an iSCSI initiator sends SCSI commands over
an IP network. An initiator falls into two broad types:
Software initiator
A software initiator uses code to implement iSCSI. Typically, this happens in a
kernel-resident device driver that uses the existing network card (NIC) and network stack
to emulate SCSI devices by speaking the iSCSI protocol. Software initiators are available
for most operating systems, and this type is the most common mode of deploying iSCSI.
An example of an iSCSI stack is the Microsoft iSCSI Software Initiator, which runs on
Windows Server 2003, Windows Server 2008 and VMware ESX4. At the time of writing,
the current version is V2.08 and is available for download from the Microsoft Web site. For
Windows Sever 2008 and ESX4 the iSCSI initiator is included in the box.
Note: Refer to System Storage Operation Center (SSIC) for the complete list of the
supported operating systems. The SSIC can be found at:
http://www-03.ibm.com/systems/support/storage/config/ssic/displayesssearchwi
thoutjs.wss?start_over=yes
For the IBM AIX operating system, refer to the "iSCSI software initiator and software
target" topic at http://publib.boulder.ibm.com/infocenter/systems/index.jsp.
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Chapter 1. Disk attachment technology
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