7065DiskAttach.fm
Draft Document for Review August 30, 2007 12:59 am
10
IBM System Storage DS3000: Introduction and Implementation Guide
The DS3300 yuses IQN names.
EUI
An alternative type of iSCSI name is the Enterprise Unique Identifier (EUI). The format of an
EUI is
eui
plus 16 hex digits. For example:
eui.acdc15882005bdef
iSCSI addressing
The iSCSI address has the format of:
<IP address>[:<port>]/<iSCSI name>
The IP address can be either IPv4, IPv6, or the fully qualified domain name. The <port> is
optional; it specifies the TCP port that the target is listening for connections on. If it is not
used, the well-known iSCSI port (3260) is assumed. The <iSCSI name> is the iqn or eui
name of the device. It is optional.
The iSCSI address specifies a single path to an iSCSI target. The iSCSI address is primarily
used during discovery.
1.3.2 iSCSI discovery
iSCSI discovery allows an initiator to find the target(s) to which it has access. This requires a
minimum of user configuration. Several methods of discovery may be used:
A list of targets at the initiator
An administrator can statically define the iSCSI targets to the host system initiator. This
process allows the administrator to specify the iSCSI target node name and IP address:port
to the host system initiator or its host bus adapter (HBA). iSCSI HBAs should support an
administrator defining this information. This type of discovery is useful in small installations
and is know as static discovery..
Queries to known iSCSI servers
An iSCSI initiator can probe its environment and, when a possible iSCSI target is found, start
a
discovery session
with the target by issuing a
SendTargets
command. The target can reply
to a
SendTargets
command by returning a list of all iSCSI target nodes it knows about.
Queries to an Internet Storage Name Server (iSNS)
The Internet Storage Name Server permits iSCSI targets to register with a central point. The
administrator can set up discovery domains so that when a host iSCSI initiator queries the
central control point for the locations of iSCSI storage controllers, only the authorized
controllers are reported. The iSNS server can be located by one of the following techniques:
iSCSI initiators multicasting to the iSNS server
setting the iSNS server IP address in the DHCP server
setting the iSNS server IP address in the SLP server (see below)
setting the iSNS server IP address in the iSCSI initiator or target
Service Location Protocol (SLP)
The Service Location Protocol can be used to locate iSCSI target devices. SLP operates with
three agents:
