iSCSI Optimization Commands

This section describes commands you use to monitor iSCSI sessions and prioritize iSCSI packets. iSCSI Optimization provides a means of giving traffic between iSCSI initiator and target systems special Quality of Service (QoS) treatment. This is accomplished by monitoring traffic to detect packets used by iSCSI stations to establish iSCSI sessions and connections. Data from these exchanges is used to create classification rules that assign the traffic between the stations to a configured traffic class. Packets in the flow are queued and scheduled for egress on the destination port based on these rules.

iscsi aging time

This command sets the aging time for iSCSI sessions.

• Default: 10 minutes
• Format: iscsi aging time time
• Mode: Global Config
• time: The number of minutes a session must be inactive prior to its removal. Range: 1-43,200.

Behavior when changing aging time:

• When aging time is increased, current sessions will be timed out according to the new value.
• When aging time is decreased, any sessions that have been dormant for a time exceeding the new setting will be immediately deleted from the table. All other sessions will continue to be monitored against the new time out value.

no iscsi aging time

Use the no form of the command to reset the aging time value to the default value.

• Format: no iscsi aging time
• Mode: Global Config

iscsi cos

This command sets the quality of service profile that will be applied to iSCSI flows. iSCSI flows are assigned by default to the highest VPT/DSCP mapped to the highest queue not used for stack management. The user should also take care of configuring the relevant Class of Service parameters for the queue in order to complete the setting.

Setting the VPT/DSCP sets the QoS profile which determines the egress queue to which the frame is mapped. The switch default setting for egress queues scheduling is Weighted Round Robin (WRR). You may complete the QoS setting by configuring the relevant ports to work in other scheduling and queue management modes via the Class of Service settings. Depending on the platform, these choices may include strict priority for the queue used for iSCSI traffic. The downside of strict priority is that, in certain circumstances (under heavy high priority traffic), other lower priority traffic may get starved. In WRR the queue to which the flow is assigned to can be set to get the required percentage.

• Format: iscsi cos {vpt vpt | dscp dscp} [remark]
• Mode: Global Config
• vpt/dscp: The VLAN Priority Tag or DSCP to assign iSCSI session packets.
• remark: Mark the iSCSI frames with the configured VPT/DSCP when egressing the switch.

no iscsi cos

Use the no form of the command to return to the default.

• Format:no iscsi cos
• Mode: Global Config

iscsi enable

This command globally enables iSCSI awareness.

• Default: disabled
• Format: iscsi enable
• Mode: Global Config

no iscsi enable

This command disables iSCSI awareness. When you use the no iscsi enable command, iSCSI resources will be released.

• Format: no iscsi enable
• Mode: Global Config

iscsi target port

This command configures an iSCSI target port and, optionally, a target system’s IP address and IQN name. When working with private iSCSI ports (not IANA-assigned ports 3260/860), it is recommended to specify the target IP address as well, so that the switch will only snoop frames with which the TCP destination port is one of the configured TCP ports, and the destination IP is the target’s IP address. This way the CPU will not be falsely loaded by non-iSCSI flows (if by chance other applications also choose to use these un-reserved ports. When a port is already defined and not bound to an IP address, and you want to bind it to an IP address, you should first remove it by using the no form of the command and then add it again, this time together with the relevant IP address. Target names are only for display when using the show iscsi command. These names are not used to match with the iSCSI session information acquired by snooping. A maximum of 16 TCP ports can be configured either bound to IP or not.

• Default: iSCSI well-known ports 3260 and 860 are configured as default but can be removed as any other configured target.
• Format: iscsi target port tcp-port-1 [tcp-port-2...tcp-port-16] [address ip-address] [name targetname]
• Mode: Global Config
• tcp-port-n: TCP port number or list of TCP port numbers on which the iSCSI target listens to requests. Up to 16 TCP ports can be defined in the system in one command or by using multiple commands.
• ip-address: IP address of the iSCSI target. When the no form of this command is used, and the tcp port to be deleted is one bound to a specific IP address, the address field must be present.
• targetname: iSCSI name of the iSCSI target. The name can be statically configured; however, it can be obtained from iSNS or from sendTargets response. The initiator must present both its iSCSI Initiator Name and the iSCSI Target Name to which it wishes to connect in the first login request of a new session or connection.

no iscsi target port

Use the no form of the command to delete an iSCSI target port, address, and name.

show iscsi

This command displays the iSCSI settings.

• Format: show iscsi
• Mode: Privileged EXEC

show iscsi sessions

This command displays the iSCSI sessions.

• Default: If not specified, sessions are displayed in short mode (not detailed).
• Format: show iscsi sessions [detailed]
• Mode: Privileged EXEC