Why Cisco UCS Rocks #1: Abstraction
Fabric computing is a set of computing, storage, memory and I/O components joined through a fabric interconnect, and the software to configure and manage them.
— Gartner Research
NOTE: Cisco uses the term FEX loosely to apply to any device that extends a fabric in this way—so you have to learn which FEX components admins or customers are appropriate to which use cases.
So each blade above is redundantly connected to a fabric (FEX A to Fabric A, FEX B to Fabric B), and it is done so via (4) 10Gbps Unified links—that's a total of 80Gbps to the backplane!
Unlike other solutions, which add layers of management software to
achieve integration, the Cisco Unified Data Center is specifically designed for virtualization and automation and enables on-demand provisioning from shared pools of infrastructure across physical and virtual environments. — Cisco
Less Infrastructure. More Intelligence. — Cisco UCS
And because the settings are stored in the fabric interconnect, if a blade fails, I can literally replace it and boot it without ANY reconfiguration (assuming I have set it up for this scenario)—even down to the WWPN and MAC address allocations!