Cisco Nexus 7000 Design Manual page 42

FlexPod Implementation and Design
The NetApp storage controllers are interconnected to the Cisco Nexus 7000 Storage VDCs using two
dedicated links, one for each SAN. In this CVD, NetApp Controller 1 & 2's LIF A interconnects to SAN
A vfc437 and vfc438 respectively. Similarly, the NetApp Controller's LIF B interconnects to SAN B
using vfc437 and vfc438 respectively. This assures universal accessibility of the fabric to each of the
NetApp storage node in case of link or device failures. To maintain SAN A/B isolation Storage VDCs
in the Nexus 7000 A and B are associated to a different VLAN/VSAN pairing, meaning the
interconnections facing the NetApp storage systems have unique FCoE VLANs defined on each Cisco
Nexus switch.
Note It is considered a best practice to name your vfc for the port channel it is residing on, for example vfc437
is on port 4/37.
The Cisco Nexus 7000 Series switch in the FlexPod design provides Fibre Channel over Ethernet
services to the UCS and NetApp FAS platforms. Internally the Cisco Nexus 7000 platforms need to be
configured to support FCoE zoning to enforce access policy between Cisco UCS-based initiators and
NetApp FAS-based targets. Without a zoning configuration there will be no communication between the
initiators and targets.
FlexPod is a converged infrastructure platform. This convergence is possible due to the support of
Ethernet enhancements across the integrated compute stack with regard to the bandwidth allocation and
flow control based on the traffic classification. As such, it is important to implement these QoS
techniques to ensure quality of service in the FlexPod configuration.
Priority Flow Control (PFC) 802.1Qbb - Lossless Ethernet using a PAUSE on a per Class of Service
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(CoS)
Enhanced Transmission Selection (ETS) 802.1Qaz - Traffic Protection through bandwidth
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management
Data Center Bridging Capability Exchange (DCBX) – Negotiates Ethernet functionality between
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devices (PFC, ETS and CoS values)
The Cisco Nexus 7000 Series Switch supports these capabilities through QoS policies. QoS is manually
enabled using Cisco MQC (Modular QoS CLI) providing class based traffic control. The Cisco Nexus
system will instantiate the basic QoS classes for Ethernet traffic and a system FCoE class (class-fcoe)
when the FCoE feature and QoS are enabled. It is important to align the QoS setting (CoS, MTU) within
the Cisco Nexus 7000 switch, the UCS Fabric Interconnects, and the Cisco Nexus 1000v configurations.
Realize that DCBX signaling can impact the NetApp controller be sure to allocate the proper bandwidth
based on the site application needs to the appropriate CoS classes and to keep MTU settings consistent
in the environment to avoid fragmentation issues and improve performance.
The following summarizes the best practices used in the validation of the FlexPod architecture:
Nexus 7000 features enabled
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VMware vSphere 5.1 on FlexPod with Nexus 7000 Using FCoE
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Fibre Channel over Ethernet (FCoE) which uses the Priority Flow Control (802.1Qbb),
Enhanced Transmission Selection (802.1Qaz) and Data Center Bridging eXchange (802.1Qaz)
to provide a lossless fabric.
N-Port ID Virtualization (NPIV) allows the network fabric port (N-Port) to be virtualized and
support multiple fibre channel initiators on a single physical port.
Link Aggregation Control Protocol (LACP part of 802.3ad).
Cisco Virtual Port Channeling (vPC) for link and device resiliency.
Link Layer Discovery Protocol (LLDP) allows the Nexus 7000 to share and discover DCBX
features and capabilities between neighboring FCoE capable devices.