The software initiator is configured by using SMIT as shown in this
procedure.
- Select Devices.
- Select iSCSI.
- Select Configure iSCSI Protocol Device.
- Select Change / Show Characteristics of an iSCSI Protocol
Device
- Verify that the Initiator Name value is correct.
The
Initiator Name value is used by the iSCSI target device during the
login operation.
Note: A default initiator name is assigned when the software is installed. You can
change the initiator name to match local network naming conventions. When you use
multiple iSCSI initiator devices, you must assign a unique name for each initiator
device.
- The Maximum Targets Allowed field corresponds to the maximum
number of iSCSI target devices that can be configured.
If you reduce this number, you also reduce the amount of network memory pre-allocated for the
iSCSI protocol driver during configuration.
-
Configure the iSCSI discovery method by using the Discovery Policy field
to discover the iSCSI target devices.
The iSCSI initiator software supports the following discovery methods:
- file
- The information about target devices is stored in a configuration file.
Note: When
the Discovery Policy field is set to file
, the names of the
iSCSI target devices are read from the file that you specify in the Discovery file
name attribute. When you use multiple instances of the iSCSI software initiator, you
must create multiple discovery files if the initiator devices access different iSCSI target
devices.
- odm
- The information about targets is stored in the Object Data Manager (ODM) objects. When using an
iSCSI disk as a boot disk or as part of the rootvg boot, the odm discovery method must
be used. See Adding a statically-discovered iSCSI target into ODM.
- isns
- The information about targets is stored on an internet Storage Name Service (iSNS) server and
automatically retrieved during the iSCSI initiator configuration.
- slp
- The information about targets is stored on a Service Location Protocol (SLP) service agent or
directory agent and automatically retrieved during the iSCSI initiator configuration.
-
Select a value for the isw_err_recov attribute, either
delayed_fail or fast_fail. This attribute allows you to set how many times the iSCSI
initiator attempts to recover from network errors. The delayed_fail value represents the
default behavior that the iSCSI software initiator uses. The delayed_fail value is
recommended for environments that have a single iSCSI path to the devices. The fast_fail
value reduces various times out values and retry values used by the iSCSI software initiator. This
value is the recommended when using multiple paths to the iSCSI device (MPIO), or when the iSCSI
devices are utilizing LVM Mirroring. In these situations, if you use the fast_fail value, the
AIX operating system switches more quickly to a working path when one path has a network
outage.
- Select the required values for the initial_r2t and
immediate_data attributes. By default, the initial_r2t
attribute is set to
yes
and the immediate_data attribute is
set to no
. You can toggle these values. When you set the
intial_r2t attribute to no
, the iSCSI software initiator
device can negotiate with the iSCSI target device to not use an initial ready-to-transfer Protocol
Data Unit (PDU) while writing data to the iSCSI disk. When you set the
immediate_data attribute to yes
, the iSCSI software
initiator device can negotiate with the iSCSI target device to send the data immediately to the
iSCSI disk. If you select the appropriate values for the intial_r2t and
immediate_data attributes, the performance of writing data to the iSCSI disks
will improve.
After the software initiator is configured, do the following:
- If the discovery policy is file, edit the /etc/iscsi/targets file to
include the iSCSI targets needed during device configuration.
Each uncommented line in the file
represents an iSCSI target. For more information, see targets File in Files Reference.
If the discovery policy is
odm, use the mkiscsi command or smit panels to create the target definitions in ODM.
For more information, see Adding a statically-discovered iSCSI target into ODM.
If the discovery
policy is isns or slp, ensure that the iSNS or SLP server is properly configured and
accessible by the iSCSI initiator.
iSCSI device configuration requires that the iSCSI targets
can be reached through a properly configured network interface. Although the iSCSI software
initiator can work by using a 10/100 Ethernet LAN, it is designed for use with a gigabit Ethernet
network that is separate from other network traffic.
- After defining the targets, type the following command:
cfgmgr -l iscsi0
This command reconfigures the software initiator driver.
It causes the driver to attempt to communicate with the targets listed in the
/etc/iscsi/targets file, and to define a new hdisk for each LUN on the targets
that are found. For more information, see the cfgmgr command description.
Note: If the appropriate disks are not defined, review the configuration of the initiator, the
target, and any iSCSI gateways to ensure correctness, and then rerun the cfgmgr
command.
If you want to further configure parameters for iSCSI software
initiator devices, use SMIT as follows:
- Select Devices.
- Select Fixed Disk.
A typical software initiator device is displayed similar to the following example:
hdisk2 Available Other iSCSI Disk Drive
If the iSCSI disk supports command tag queuing and NACA=1 in the control byte, consider changing
the queue depth setting of the disk to a larger value. A larger value might help improve device
performance. The optimal queue depth setting cannot exceed the actual queue size on the drive.
Setting the queue depth to a value larger than the drive's queue size would possibly degrade
performance. To determine the drive's queue size, refer the drive documentation.