Configuring iSCSI Optimization 463
How Does iSCSI Optimization Interact With Dell EqualLogic Arrays?
The iSCSI feature includes auto-provisioning support with the ability to
detect directly connected Dell EqualLogic (EQL) SAN storage arrays and
automatically reconfigure the switch to enhance storage traffic flows.
The Dell Networking series switches use LLDP, a vendor-neutral protocol, to
discover Dell EQL devices on the network. LLDP is enabled by default. For
more information about LLDP, see "Discovering Network Devices" on
page761.
When the switch detects a Dell EQL array, the following actions occur:
An MTU of 9216 is enabled on the system, if it is not already enabled.
Spanning tree portfast is enabled on the EQL-connected interface
identified by LLDP.
Unicast storm control is disabled on the EQL-connected interface
identified by LLDP.
It is advisable to enable spanning tree portfast and disable unicast storm
control on ports connected to the initiators as well.
If the iSCSI CoS policy feature is enabled on the switch and an EQL array is
detected, the switch applies additional iSCSI CoS policies to the EQL inter-
array traffic on TCP ports 9876 and 25555. If the iSCSI CoS policy is disabled
and EQL arrays are present, the additional CoS policy is removed globally.
What Occurs When iSCSI Optimization Is Enabled or Disabled?
When iSCSI is enabled on the switch, the following actions occur:
Flow control is globally enabled, if it is not already enabled.
iSCSI session snooping is enabled
iSCSI LLDP monitoring starts to automatically detect De ll EqualLogic
arrays.
If the iSCSI feature is disabled on the switch, iSCSI resources are released
and the detection of Dell EqualLogic arrays by 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. iSCSI
Optimization is enabled by default.