Gen2 Cisco UCS is More Ports, More Oversubscription – Overkill for most Enterprises?




I was working on a HP Virtual Connect FlexFabric and Cisco FEX bake off scenario and found something which is near to the end decision. I thought I would write an article on this. Here you go. For the betterment of visualization, I have created a Visio diagram and made it available here as above.


If a new 8 port FEX is used on a set of 8 servers using the two 10G VIC, a single enclosure of 8 servers would be connected to the Fabric Interconnect using 16 cables for maximum bandwidth. That is 2 cables per server – where is the convergence and cable reduction? Is the new 8 port FEX only a reasonable choice for the new 1280 VIC and is this really overkill for most customers?


Each Cisco UCS 2208XP has 32, 10Gb ports connected through the mid plane to each half-width slot in the chasis. Therefore each server can employ a 1280 VIC with 40Gbps to each fabric in an active/active format.


This results in a total (theoretical) 640Gbps total server bandwidth constrained by a maximum 160 Gbps for a 4:1 oversubscription.


Cisco flaunts that the new VIC can deliver 80Gbps but this may be more I/O than in reality they are able to deliver due to data rate constraints on the data bus.


About Prasenjit Sarkar

Prasenjit Sarkar is a Product Manager at Oracle for their Public Cloud with primary focus on Cloud Strategy, Oracle Openstack, PaaS, Cloud Native Applications and API Platform. His primary focus is driving Oracle’s Cloud Computing business with commercial and public sector customers; helping to shape and deliver on a strategy to build broad use of Oracle’s Infrastructure as a Service (IaaS) and Platform as a Service (PaaS) offerings such as Compute, Storage, Java as a Service, and Database as a Service. He is also responsible for developing public/private cloud integration strategies, customer’s Cloud Computing architecture vision, future state architectures, and implementable architecture roadmaps in the context of the public, private, and hybrid cloud computing solutions Oracle can offer.

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