FCoE Cookbook for HP Virtual Connect Version 4.20 Firmware Enhancements May 2014

Benefits

This configuration offers increased performance and better availability. The server-to-uplink ratio is adjustable, with the

current NX software limitations, up to 2:1 with the Nexus 5500 series and VC Flex-10/10D (as few as two servers share

one physical Fabric uplink) and up to 4:1 with the Nexus 5000 series.

Using multiple FCoE uplink ports on each VC module connected to Nexus allows dynamically distribution of the FCoE

traffic across the ports using a round robin format.

By providing ability to define multiple FCoE VLANs on a single set of uplinks, VC allows multi-VSAN capability to be

enabled on Cisco’s MDS or Nexus switches. VSANs allow an enterprise customer to maintain single physical SAN

infrastructure, while providing separation and traffic isolation to the servers based on the business unit, types of the

operating systems or need for logical isolation. Servers can therefore access to a different VSANs and connect to storage

targets located in different logical SAN environment.

Port Channeling with VSAN trunking is also used between the Nexus and MDS core switches to increase the high

availability and to create enough SAN subscription.

Considerations

The Nexus switches operate as Fiber Channel Forwarders (FCF). This is the default Cisco Nexus 5xxx Series switches

mode, it’s also called the fabric mode. In this mode, the switch provides standard Fibre Channel switching capability and

features.

Multiple VSAN support

The number of FCoE networks per Shared Uplink Set is limited to 32. VSAN tagging is not supported for native FC fabrics.

The number of FCoE networks is additionally limited by the 1000 network domain limit.

For this feature to successfully integrate with Cisco Nexus switches it is important to note that for each FCoE VLAN a

unique FC VSAN must be created and association between the two must be strictly configured as 1-to-1. Mapping of a

single VLAN into multiple VSANs is not supported. This requirement is documented in Cisco’s best practice

recommendations.

All of the FCoE networks will share the same lossless Priority Flow Control (PFC) queue on any specific shared uplink set.

Sharing PFC queue between multiple VSANs will make it possible that traffic from one VSAN may have impact on traffic

from other VSANs. For that reason, it is highly recommended to create enough SAN subscription (i.e. by using a suitable

number of uplink between VC and Nexus but also between Nexus and Cisco MDS) to avoid any over-subscription issues

that would prevent SAN to pause and therefore to impact other VSANs. Therefore the use of a SAN Port Channel with

VSAN trunking between the Nexus and MDS switches is highly recommended.

SAN Port Channel and Trunking

The use of a SAN Port Channel between the Nexus and MDS core switch is highly recommended to create enough SAN

subscription. F-Port Port Channeling increases the uplink resiliency, optimizes the bandwidth utilization and increases

the aggregated bandwidth with load balancing.

 SAN Port Channeling between Nexus and upstream switches is only supported with Cisco switches (MDS or Nexus

series).

 TE ports that are members of the same SAN Port Channel cannot be connected to different core switches.