Reference Guide
In an iSCSI session, a switch connects CNA servers (iSCSI initiators) to a storage array (iSCSI targets) in a storage area network (SAN) or
TCP/IP network. iSCSI optimization running on the switch uses dot1p priority-queue assignments to ensure that iSCSI trac receives
priority treatment.
iSCSI conguration notes
• When you enable iSCSI optimization, the switch auto-detects and auto-congures for Dell EqualLogic storage arrays directly connected
to an interface. iSCSI automatically congures switch parameters after connection to a storage device is veried. You must manually
enable an interface to support a storage device that is directly connected to a port, but not automatically detected by iSCSI.
• By default, iSCSI monitoring sessions listen on TCP ports 860 and 3260. Enable iSCSI session monitoring and the aging time for iSCSI
sessions.
• Congure the CoS/DSCP values applied to ingress iSCSI ows — create a class-iscsi class map in POLICY-CLASS-MAP mode.
• iSCSI operation requires LLDP to be enabled. The DCBX application TLV carries information about the dot1p priorities to use when
sending iSCSI trac. This informational TLV is packaged in LLDP PDUs. You can recongure the 802.1p priority bits advertised in the
TLVs.
Congure iSCSI optimization
The iSCSI protocol provides TCP/IP transport of storage trac between servers and storage arrays in a network using iSCSI commands.
1 Congure an interface or interface range to detect a connected storage device.
interface ethernet node/slot/port:[subport]
interface range ethernet node/slot/port:[subport]-node/slot/port[:subport]
2 Enable the interface to support a storage device that is directly connected to the port and not automatically detected by iSCSI. Use
this command for storage devices that do not support LLDP. The switch auto-detects and auto-congures Dell EqualLogic storage
arrays directly connected to an interface when you enable iSCSI optimization.
iscsi profile-storage storage-device-name
3 Congure DCBX to use LLDP to send iSCSI application TLVs with the dot1p priorities for iSCSI trac in INTERFACE mode.
lldp tlv-select dcbxp-appln iscsi
4 Return to CONFIGURATION mode.
exit
5 (Optional) If necessary, re-congure the iSCSI TCP ports and IP addresses of target storage devices in CONFIGURATION mode.
Separate TCP port numbers with a comma (0-65535; default 860 and 3260).
iscsi target port tcp-port1 [tcp-port2, ..., tcp-port16] [ip-address ip-address]
6 Congure the QoS policy applied to the ingress iSCSI ows. Apply the service policy to ingress interfaces in CONFIGURATION mode.
(Optional) Reset the default CoS dot1p priority (default 4) and/or the trusted DCSP value used for iSCSI trac. Assign an internal
qos-group queue (0 to 7) to dot1p (0 to 7) and DSCP (0 to 63) values in POLICY-CLASS-MAP mode.
class-map type application class-iscsi
policy-map type application policy-iscsi
class class-iscsi
set qos-group
traffic-class-number
set cos dot1p-priority
set dscp dscp-value
end
service-policy type application policy-iscsi
7 Enable iSCSI monitoring sessions on TCP ports in CONFIGURATION mode.
iscsi session-monitoring enable
8 (Optional) Set the aging time for the length of iSCSI monitoring sessions in CONFIGURATION mode (5 to 43,200 minutes; default
10).
iscsi aging time [minutes]
9 (Optional) Recongure the dot1p priority bits advertised in iSCSI application TLVs in CONFIGURATION mode. The default bitmap is
0x10 (dot1p 4). The default dot1p 4 value is sent in iSCSI application TLVs only if you enabled the PFC pause for dot1p 4 trac
(pfc-cos dot1p-priority command).
Converged data center services
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