Administrator Guide

iSCSI optimization allows you to reduce deployment time and management complexity in data centers. In a
data center network, Dell EqualLogic and Compellent iSCSI storage arrays are connected to a converged
Ethernet network using the data center bridging exchange protocol (DCBx) through Ethernet switches.
iSCSI session monitoring over virtual link trunking (VLT) synchronizes the iSCSI session information between
the VLT peers, allowing session information to be available in both VLT peers.
iSCSI optimization functions as follows:
• Manual configuration to detect Compellent storage arrays where auto-detection is not supported.
• Jumbo frames — Ports are set to a maximum transmission unit (MTU) of 12,000 bytes.
• If you configured flow-control, iSCSI uses the current configuration. If you did not configure flow-
control, iSCSI auto-configures flow control.
• iSCSI monitoring sessions — the switch monitors and tracks active iSCSI sessions in connections on the
switch, including port information and iSCSI session information.
• iSCSI QoS — A user-configured iSCSI class of service (CoS) profile is applied to all iSCSI traffic. Classifier
rules are used to direct the iSCSI data traffic to queues that can be given preferential QoS treatment over
other data passing through the switch. Preferential treatment helps to avoid session interruptions during
times of congestion that would otherwise cause dropped iSCSI packets.
• iSCSI DCBx TLVs are supported.
The following figure shows iSCSI optimization between servers in a server enclosure and a storage array in
which an Aggregator connects installed servers (iSCSI initiators) to a storage array (iSCSI targets) in a SAN
network. iSCSI optimization running on the Aggregator is configured to use dot1p priority-queue assignments
iSCSI Optimization 489