Cisco Cisco Prime Virtual Network Analysis Module (vNAM) 6.3 White Paper

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Cisco Virtualized Multiservice Data Center (VMDC) Virtual Services Architecture (VSA) 1.0
Design Guide
Chapter 3      VMDC VSA 1.0 Design Details
  Storage
Figure 3-6
SAN FC Attachment
In these scenarios, Cisco's unified fabric capabilities are leveraged with converged network adapters 
(CNAs) to provide "SAN-ready" servers, and NPV on the UCS Fabric Interconnect or Nexus 5000 
top-of-rack (ToR) switches, enabling each aggregated host to be uniquely identified and managed 
through the fabric and over uplinks to the SAN. Multiple FC links are used from each (redundant) Nexus 
5000 or UCS Fabric Interconnect to the MDS SAN switches, to match the current maximum processing 
capability of the SAN and thus eliminate lack of bandwidth as a potential bottleneck between the SAN 
components and their point of attachment to the network infrastructure.
Similarly, for FCOE, multiple 10 GigE links provide resilience, and performance and cost efficiencies, 
by consolidating IP data, file and block traffic onto Ethernet. In this case, additional consolidation for 
smaller infrastructures may be attained by eliminating SAN switching systems, as illustrated.
Although 
 shows a simplified SAN switching topology, it is important to note that if greater 
SAN port switching capacity is required, the architecture supports (and has been validated with) more 
complex, two-tier core-edge SAN topologies, as documented in the VMDC 2.0 "
," and more generally in Cisco SAN switching best practice guides, available at 
.
NAS Architecture
The VMDC NAS architecture is 
-aligned, following current best practice guidelines for 
scalability, HA, and traffic isolation. Key design aspects of this portion of the architecture include:
  •
Infrastructure resiliency through multi-level redundancy of field replaceable unit (FRU) 
components, multipath HA controller configurations, RAID-DP, and software enhancements that 
help with failures from a software perspective and a hardware perspective.
  •
Risk mitigation through fabric isolation and multi-level redundancy of connections (multiple 
fabrics, vPCs or port-channels, interface groups at the storage layer).
  •
vPCs address aggregate bandwidth, link, and device resiliency. UCS fabric interconnects and 
NetApp FAS controllers benefit from the Nexus vPC abstraction, gaining link and device resiliency, 
and full utilization of a nonblocking Ethernet fabric. From a storage perspective, both standard Link 
Aggregation Control Protocol (LACP) and the vPC link aggregation technologies play important 
roles in the FlexPod design.