Dell PowerVault NX1950 - Manual (Page 14)

14
Planning the Network Configuration
The following SAN network guidelines are recommended for optimal
performance and high availability:
• Use a switched, Gigabit Ethernet network.
Connect storage arrays and hosts to a switched network and ensure that all
network connections between hosts and arrays are Gigabit Ethernet.
An array can operate at 10 and 100 Mbits, but performance is significantly
degraded.
• Utilize fast convergence/fast spanning tree.
The Spanning Tree Protocol (STP) has a measurable convergence time.
When a switch participating in spanning tree fails, the protocol needs to
recalculate which is going to be the root switch. During this time, you can
experience a network service interruption on that segment while this
re-convergence happens. Rapid Spanning Tree Protocol (RSTP) allows a
switch port to bypass the Spanning Tree listening and learning states and
quickly enter the STP forwarding state. Utilizing Rapid Spanning Tree
Protocol (RSTP, 802.1w) can speed up the time it takes to recalculate
spanning tree, thus reducing network service interruption. To verify if your
switches are RSTP-capable and how to configure for RSTP, see your switch
documentation.
• Use flow control.
Enable Flow Control on each switch port that handles iSCSI traffic.
Enable Flow Control on the NICs to obtain any performance benefit. PS
Series storage arrays support Flow Control.
• Enable Jumbo Frames.
If supported by all the devices in the network path between hosts and
arrays, enable Jumbo Frames on each switch that handles iSCSI traffic.
This support is usually disabled by default. Also enable Jumbo Frames on
the NICs that are responsible for iSCSI traffic to obtain any performance
benefit and ensure consistent behavior.
Book.book Page 14 Monday, February 4, 2008 1:26 PM