User`s guide

Chapter VII. iSCSI PDU Offload Target
Chelsio T5/T4 Unified Wire For Linux Page 110
There are many specific parameters that can be configured, some of which are iSCSI specific
and the rest being Chelsio specific. An example of an iSCSI specific item is “HeaderDigest”
which is defaulted to “None” but can be overridden to “CRC32C”. An example of a Chelsio
specific configurable item is “ACL” (for Access Control List). “ACL” is one of the few items that
have no default.
Before starting any iSCSI target, an iSCSI configuration file must be created. An easy way to
create this file is to use the provided sample configuration file and modify it. This file can be
named anything and placed in any directory but it must be explicitly specified when using iscsictl
by using the -f option. To avoid this, put configuration file in the default directory
(/etc/chelsio-iscsi) and name it the default file name (chiscsi.conf).
4.2.1. “On the fly” Configuration Changes
Parameters for the most part can be changed while an iSCSI node is running. However, there
are exceptions and restrictions to this rule that are explained in a later section that describes the
details of the iSCSI control tool iscsictl.
4.3. A Quick Start Guide for Target
This section describes how to get started quickly with a Chelsio iSCSI target. It includes:
Basic editing of the iSCSI configuration file.
Basic commands of the iSCSI control tool including how to start and stop a target.
4.3.1. A Sample iSCSI Configuration File
The default Chelsio iSCSI configuration file is located at /etc/chelsio-iscsi/chiscsi.conf.
If this file doesn’t already exist then one needs to be created.
To configure an iSCSI target, there are three required parameters (in the form of key=value
pairs) needed as follows:
TargetName – A worldwide unique iSCSI target name.
PortalGroup – The portal group tag associating with a list of target IP address (es) and port
number(s) that service the login request. The format of this field is a Chelsio specific iSCSI
driver parameter which is described in detail in the configuration file section.
TargetDevice – A device served up by the associated target. A device can be:
 A block device (for example, /dev/sda)
 A virtual block device (for example, /dev/md0)
 A RAM disk
 A regular file