Cisco Systems MDS 9000 Advanced iSCSI Configuration

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Cisco MDS 9000 Family Fabric Manager Configuration Guide

OL-6965-03, Cisco MDS SAN-OS Release 2.x

Chapter 20 iSCSI Configuration

Configuring iSCSI

Advanced iSCSI Configuration

Advanced configuration options are available for iSCSI interfaces on a per-IPS port basis.Cisco MDS

switches support the following advanced features for iSCSI interfaces:

•iSCSI listener port—You can configure the TCP port number for the iSCSI interface which listens

for new TCP connections. The default port number is 3260. Following that, the iSCSI port only

accepts TCP connections on the newly configured port

See the )

•TCP tuning parameters—You can configure the following TCP parameters.

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The minimum retransmit timeout, keepalive timeout, maximum retransmissions, path MTU,

SACK (SACK is enabled by default for iSCSI TCP configurations), window management (The

iSCSI defaults are max-bandwidth = 1G, min-available-bandwidth = 70 Mbps, and

round-trip-time =1 ms.), buffer size (default send buffer size for iSCSI is 4096 KB), window

congestion (enabled by default and the default burst size is 50 KB.), and maximum delay jitter

(enabled by default and the default time is 500 microseconds.).

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QoS—QoS configurations differ for iSCSI and FCIP interfaces.

•Identification of dynamic iSCSI initiator—iSCSI initiators are identified based on their IQN name

or their IP address. In the absence of any configuration for the initiator (WWN or VSAN

membership), the identifier key is the default connection. By default, the key is the IQN name but

can be changed to IP address by toggling this mode.

•Proxy or transparent Initiator—For each iSCSI initiator with iSCSI target sessions, the switch

creates a virtual FC initiator with a distinct pair of WWNs per VSAN. For targets that have access

control per LUN, the WWN pair of each FC initiator must be configured in the target. The proxy

initiator mode can be enabled to facilitate this configuration, in this case, all iSCSI initiators that

connect to this iSCSI interface inherit the same WWN pair and create only one virtual FC initiator

in each VSAN.

To set the QoS values, follow these steps:

Step 1 In Fabric Manager, select Interfaces > FC Logical from the Physical Attributes pane. You see the

Interface tables in the Information pane.

In Device Manager, select Interfaces > Ethernet or iSCSI. You see the interfaces dialog box.

Step 2 Click the iSCSI TCP tab. You see the iSCSI TCP configuration table.

Step 3 Set the QoS field from 1 to 6.

Step 4 Click the Apply Changes icon in Fabric Manager or click Apply in Device Manager to save these

changes, or click Undo Changes in Fabric Manager or click Cancel in Device Manager to discard

changes.