Dell M6220 User Configuration Manual page 424

The following commands show how to configure the iSCSI example depicted
in Figure 16-6. Remember that iSCSI optimization is enabled by default.
1 Set the MTU to 9216 to enable the use of jumbo frames.
console#config
console(config)#ip mtu 9216
2 Optionally configure the switch to associate CoS queue 5 with detected
iSCSI session traffic.
console(config)#iscsi cos enable
console(config)#exit
The default target port and IP address criteria is used to determine which
packets are snooped for iSCSI session data (ports 860 and 3260; any IP
address).
3 If the array is a Compellent storage array, execute the Compellent macro
on the ports attached to the array:
console#config
console(config)#macro global apply profile-compellent-nas
$interface_name te1/0/21
console(config)#macro global apply profile-compellent-nas
$interface_name te1/0/22
console(config)#macro global apply profile-compellent-nas
$interface_name te1/0/23
424
Configuring iSCSI Optimization