Users Guide

Synchronizing iSCSI Sessions Learned on VLT-Lags with
VLT-Peer
The following behavior occurs during synchronization of iSCSI sessions.
• If the iSCSI login request packet is received on a port belonging to a VLT lag, the information is synced to the VLT peer and
the connection is associated with this interface.
• Additional updates to connections (including aging updates) that are learnt on VLT lag members are synced to the peer.
• When receiving an iSCSI login request on a non-VLT interface followed by a response from a VLT interface, the session is
not synced since it is initially learnt on a non-VLT interface through the request packet.
• The peer generates a new connection log that sees the login response packet. If the login response packet uses the ICL
path, it is seen by both the peers, which in turn generate logs for this connection.
Enable and Disable iSCSI Optimization
The following describes enabling and disabling iSCSI optimizaiton.
NOTE: iSCSI monitoring is disabled by default. iSCSI auto-configuration and auto-detection is enabled by default.
If you enable iSCSI, flow control is automatically enabled on all interfaces. To disable flow control on all interfaces, use the no
flow control rx on tx off
command and save the configuration. To disable iSCSI optimization, which can turn on flow
control again on reboot, use the no iscsi enable command and save the configuration.
When you enable iSCSI on the switch, the following actions occur:
• Link-level flow control is globally enabled, if it is not already enabled, and PFC is disabled.
• iSCSI session snooping is enabled.
• iSCSI LLDP monitoring starts to automatically detect EqualLogic arrays.
The following message displays when you enable iSCSI on a switch and describes the configuration changes that are
automatically performed:
%STKUNIT0-M:CP %IFMGR-5-IFM_ISCSI_ENABLE: iSCSI has been enabled causing flow control to be
enabled on all interfaces. EQL detection and enabling iscsi profile-compellent on an interface
may cause some automatic configurations to occur like jumbo frames on all ports and no storm
control and spanning tree port-fast on the port of detection.
You can reconfigure any of the auto-provisioned configuration settings that result when you enable iSCSI on a switch.
When you disable the iSCSI feature, iSCSI resources are released and the detection of EqualLogic arrays using LLDP is disabled.
Disabling iSCSI does not remove the MTU, flow control, portfast, or storm control configuration applied as a result of enabling
iSCSI.
NOTE: By default, CAM allocation for iSCSI is set to 0. This disables session monitoring.
iSCSI Optimization 386