I Nitiator - Asus DS300j G2 Series User Manual

I
nItIator
An initiator functions as the client, in this case, your host PC or server. The initiator makes requests to and
receives responses from an iSCSI target on the ASUS DS300f G2 RAID subsystem.
Each initiator has a unique iSCSI qualified name (IQN). You specify the initiator by that name when you map a
LUN or logical drive to the initiator. Initiators come in two varieties, software and hardware.
s
oftwAre
A software initiator uses code to implement iSCSI. The software emulates SCSI devices for a computer by
speaking the iSCSI protocol. Software initiators are available for most mainstream operating systems, and this
type is the most common mode of deploying iSCSI on computers.
For more information, see your iSCSI driver user documentation.
h
ArdwAre
A hardware initiator uses dedicated hardware in combination with software running on it, to implement iSCSI.
A common example is an iSCSI host bus adapter (HBA) card.
The iSCSI HBA is a 1-gigabit or 10 gigabit Ethernet network Interface card (NIC) that plugs into a PCI-Express
slot. It looks like a SCSI device to the host PC or server's operating system.
The iSCSI HBA uses a TCP/IP Offload Engine (TOE) to perform iSCSI and TCP processing and managing
interrupts, leaving the host PC or server's microprocessor free to run other applications.
For more information, see your iSCSI HBA user documentation.
t
arGet
The target represents a storage device, in this case the ASUS DS300f G2 RAID subsystem. Each target has a
unique iSCSI qualified name (IQN).
ASUS DS300f G2 supports one iSCSI target. A maximum of 256 logical drives can be mapped to a target.
Target options include Digests, CHAPs and Nop-In.
d
igests
A header digest adds a 32-bit CRC digest to detect data corruption in the header portion of each iSCSI packet.
A data digest adds a 32-bit CRC digest to detect data corruption in the data portion of each iSCSI packet.
If a data packet arrives with an invalid CRC digest, the data packet is rejected.
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Header and data digests work best with initiators equipped with a TOE. Refer to your iSCSI HBA. For more
information, see your iSCSI HBA user documentation.
chAP
s
Challenge Handshake Authentication Protocol (CHAP) is an authentication
mechanism used to authenticate iSCSI sessions between initiators and targets.
A uni-directional or peer CHAP authenticates from the target (ASUS DS300f G2) to the initiator (host PC or
server).
A bi-directional or local CHAP authenticates target to initiator and initiator to target.
n -i
oP n
Nop-In is used to check iSCSI connection status on the specified target. Nop-In periodically sends a PDU to the
initiator that requests a response. If there is no reply, the ASUS DS300f G2 will disconnect the iSCSI connection
in order to preserve system resources for other operations. The default setting is enabled.
P
ortal
A portal is the logical point of connection between the ASUS DS300f G2 and the iSCSI network. Portals use an
IP address and a TCP port number to identify an IP storage resource. ASUS DS300f G2 supports up to 32 iSCSI
portals. ASUS DS300f G2 uses TCP port 3260.
ASUS DS300f G2 supports both IPv4 and IPv6 addresses. See "Internet Protocols" on page 373.
Portals on ASUS DS300f G2 support three types of port associations:
• PHY – A simple connection through one port.
• VLAN – Virtual Local Area Network. The portal is part of a virtual network. Used when a dedicated network
is not available for iSCSI.
• Trunk – An aggregation of two or more iSCSI ports on the same RAID controller. Also known as a link
aggregation. This feature combines ports to increase bandwidth.
Once you have made a port association, you cannot change it. If you have no portals with the port association
you want, create a new portal.
Each iSCSI portal can belong to a different VLAN. ASUS DS300f G2 supports 32 VLANs.
DS300f G2 Series User Manual