This chapter provides information on using iSCSI in MD Storage Manager. For iSCSI prerequisite requirements and detailed step-by-step instructions on setting up and configuring iSCSI, see the Installation Guide.
Using the iSCSI Tab
The iSCSI tab is shown in the MD Storage Manager only when the controllers contain iSCSI host ports. You can define or change settings for the iSCSI target or enter the CHAP permissions in the iSCSI tab. Here are some of the iSCSI settings:
Change Target Authentication — Select the authentication method to be supported by the target.
Enter Mutual Authentication Permissions — Define the permissions for initiators that require mutual authentication.
Change Target Identification — Associate an alias with the target for simpler identification.
Change Target Discovery — Modify the way to discover iSCSI targets using the Internet Storage Name Service (iSNS) server settings.
Configure iSCSI Host Ports — Set the parameters for iSCSI host ports.
View/End iSCSI Sessions — View iSCSI session details and end iSCSI sessions.
View iSCSI Statistics — View and save iSCSI statistics.
Changing the iSCSI Target Authentication
Click the iSCSI tab, and then click Change Target Authentication.
Select None if no authentication is required for any initiator to access the
target.
NOTE: If you select None, any initiator can access this target. Use this option only if you do not require secure data. However, if you select both None and CHAP at the same time, the storage array will allow an iSCSI initiator to log on with or without CHAP authentication.
Select CHAP if you want any initiator that tries to access the target to
provide the target permissions. If CHAP is selected, but no CHAP secret is
defined, an error message appears.
Click CHAP Secret to see the Enter CHAP Secret dialog (see Creating CHAP Secrets). You can define the permissions in this dialog.
Mutual authentication or two-way authentication is a way for a client or a user to verify themselves to a host server, and for the host server to validate itself to the user. This validation is accomplished in such a way that both parties are sure of the other's identity.
Click the iSCSI tab, and then click Enter Mutual Authentication
Permissions.
Select an initiator from the list. The initiator details are shown.
Select CHAP Secret to enter the initiator CHAP permissions in the dialog
that appears.
NOTE: To add, modify, or delete an initiator, click the Modify tab, and then click Edit Host Topology.
Creating CHAP Secrets
When you set up an authentication method, you can choose to create a Challenge Handshake Authentication Protocol (CHAP) secret. The CHAP secret is a password that is recognized by the initiator and the target. If you are using mutual authentication to configure the MD3000i storage array, you must enter the same CHAP secret that is defined in the iSCSI initiator, and you must define a CHAP secret on the target (the storage array) that must be configured in every iSCSI initiator that will connect to the target. For more information on CHAP, see "Understanding CHAP Authentication" in the Installation Guide.
Initiator CHAP Secret
The initiator CHAP secret is set on the host using the iSCSI initiator. If you are using the mutual authentication method, you must define the initiator CHAP secret when you set up the host. This must be the same CHAP secret that is defined for the target when defining mutual authentication settings.
Target CHAP Secret
If you are using CHAP secrets, you must define the CHAP secret for the target.
Valid Characters for CHAP Secrets
The CHAP secret must be between 12 and 57 characters. The CHAP secret supports characters with ASCII values of 32 to 126 decimal. See Table 3-1 for a list of valid ASCII characters.
Table 3-1. Valid ASCII Characters for CHAP Secrets
Space
!
"
#
$
%
&
'
(
)
*
+
,
-
.
/
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
[
\
]
^
_
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
{
|
}
~
Changing the iSCSI Target Identification
You cannot change the iSCSI target name, but you can associate an alias with the target for simpler identification. Aliases are useful because the iSCSI target names are not intuitive. You should provide an iSCSI target alias that is meaningful and easy to remember.
Click the iSCSI tab, and then click Change Target Identification.
Type the alias in the iSCSI target alias field and click OK.
NOTE: Aliases can contain a maximum of 30 characters. Aliases can include letters, numbers, and the special characters underscore (_), minus (-), and pound sign (#). No other special characters are permitted.
NOTE: Open iSCSI (which is used by Red Hat Enterprise Linux 5 and SUSE® Linux Enterprise Server 10 with SP 1) does not support using target alias.
Changing the iSCSI Target Discovery (Optional)
NOTE: Changing the iSCSI Target Discovery is optional.
Click the iSCSI tab, and then click Change Target Discovery.
Select the Use iSNS server check box to activate iSCSI target discovery.
You can use one of these methods:
Use the DHCP option (IPv4 only) to automatically activate target
discovery. You also can refresh the DHCP.
Type the IPv4 or IPv6 address to activate the target discovery. After
you manually enter an IP address, you also can click Advanced to set
the customized TCP listening ports.
If you do not want to allow discovery sessions that are not named, select
Disallow un-named discovery sessions.
Un-named discovery sessions are discovery sessions that are permitted to run without a target name. With an un-named discovery session, the target name or the target portal group tag is not available to enforce the iSCSI session identifier (ISID) rule. For more information on un-named discovery sessions, click the Support tab, then click View Online Help.
Configuring the MD3000i iSCSI Host Ports
Use the configuration dialog for the iSCSI host ports to set up the MD3000i iSCSI host ports to use with storage arrays in a storage area network (SAN).
Click the iSCSI tab, and then click Configure iSCSI Host Ports.
Select the controller in the iSCSI host port field, and then use one of
these methods to configure the port:
Automatically obtain the configuration using one of the following
methods:
IPv4 — Obtain the configuration from the DHCP server, or refresh DHCP.
IPv6 — Obtain the configuration automatically from a router.
Manually specify the configuration using one of the following
methods:
IPv4 — Enter the IP address, subnet mask, and gateway for the host port.
IPv6 — Enter the IP address, routable IP addresses, and router IP address.
After you manually enter an IP address, you also can click Advanced to set the advanced parameters for the iSCSI target discovery.
Advanced iSCSI Host Ports Settings
NOTE: Configuring the advanced iSCSI host ports settings is optional.
Use the advanced settings for the individual iSCSI host ports to specify the TCP frame size, the virtual LAN, and the network priority.
Table 3-2. Advanced iSCSI Host Port Settings
Setting
Description
Virtual LAN (VLAN)
A method of creating independent logical networks within a physical network. Several VLANs can exist within a network. VLAN 1 is the default VLAN.
NOTE: For more information on creating and configuring a VLAN with MD Support Manager, click the Support tab, then click View Online Help.
Ethernet Priority
The network priority can be set from lowest to highest. Although network managers must determine these mappings, the IEEE has made broad recommendations:
0 — lowest priority (default)
1-4 — ranges from "loss eligible" traffic to controlled-load applications, such as streaming multimedia and business-critical traffic
5-6 — delay-sensitive applications such as interactive video and voice
7 — highest priority reserved for network-critical traffic (do not use with the MD3000i)
TCP Listening Port
The default Transmission Control Protocol (TCP) listening port is 3260.
Jumbo Frames
The maximum transmission units (MTUs). It can be set between 1500 and 9000 bytes per frame. If the Jumbo Frames are disabled, the default MTU is 1500 bytes per frame.
NOTE: Changing any of these settings resets the iSCSI port. I/O is interrupted to any host accessing that port. You can access the I/O automatically after the port restarts and the host logs in again.
Viewing or Ending an iSCSI Session
Click the iSCSI tab, and then click View/End iSCSI Sessions.
Select the session you want to view in the Current sessions box. The
details are shown below in the Details box.
If you want to end the session, perform the following steps:
Select the session that you want to end, and then click End Session to
show the End Session confirmation window.
In the confirmation window, type yes to confirm that you want to end
the iSCSI session, and then click OK.
NOTE: If you end a session, any corresponding connections terminate the link between the host and the storage array, and the data on the storage array is no longer available.
NOTE: When a session is manually terminated using the MD Storage Manager, the iSCSI initiator software will automatically attempt to re-establish the terminated connection to the storage array. This may cause an error message.
Click Save As to save the entire iSCSI sessions topology as a text file.
Viewing iSCSI Statistics and Setting Baseline
Statistics
If the configured storage array has iSCSI technology, the View iSCSI Statistics option is available only on the iSCSI tab.
Click the iSCSI tab, and then click View iSCSI Statistics.
Select the iSCSI statistic type you want to view. Select one of these types:
Ethernet MAC statistics
Ethernet TCP/IP statistics
Target (protocol) statistics
Choose either Raw statistics or the Baseline statistics.
Raw statistics are all the statistics that have been gathered since the controllers were started. Baseline statistics are point-in-time statistics that have been gathered since you set the baseline time.
After you select the statistics type and either raw or baseline statistics, the details of the statistics appear in the statistics tables.
To set the baseline for the statistics, complete the following steps:
Select Baseline Statistics.
Click Set Baseline.
Confirm that you want to set the baseline statistics in the dialog that
appears.
The baseline time shows the latest time you set the baseline. The sampling interval is the difference in time from when you set the baseline until you launch the dialog or click Refresh.
NOTE: You must first set a baseline before you can compare baseline statistics.
Edit, Remove, or Rename Host Topology
If you give access to the wrong host or the wrong host group, you can remove or edit the host topology. Use one of the following actions to correct the host topology:
Table 3-3. Host Topology Actions
Desired Action
Steps to Complete Action
Move the host, the host group, or the iSCSI initiator.
Click the Modify tab, and then click Edit Host Topology.
Select the item that you want to move, and then click Move.
Select a host group to move the host to and click OK.
Manually change the host type.
Click the Modify tab, and then click Edit Host Topology.
Select the host that you want to change and click Change.
Select a new host type (or operating system) and click OK.
Manually delete the host, the host group, or the iSCSI initiator.
Click the Modify tab, and then click Edit Host Topology.
Select the item that you want to remove and click Remove.
Rename the host, the host group, or the iSCSI initiator.
Click the Modify tab, and then click Edit Host Topology.
Select the item that you want to rename and click Rename.
Type a new label for the host and click OK.
Add an iSCSI Initiator.
Click the Modify tab, and then click Edit Host Topology.
Select the host you want to add an iSCSI initiator to and click Add.
Type or select an iSCSI initiator name and label for the iSCSI initiator and click OK.
