Rack-Level Cost and Power Savings

Open vSwitch (OVS) is a robust, flow-based implementation of a Virtual Switch (vSwitch), which is widely adopted in virtualization environments such as KVM. Since the original implementation in 2009, OVS has continuously evolved with new features to become the most widely adopted vSwitch technology for enabling server-based networking. The Corigine Agilio CX SmartNIC platform dramatically accelerates the OVS datapath and works with standard OVS distributions, enabling customers to reap the benefits of open source software including feature velocity resulting from a large community of developers.


A common performance target for VMs in servers is approximately 1Mpps per VM. Using a 16-core server, an Agilio-accelerated server will allow 15 VMs to be deployed on the syste m, each VM using one core. The remaining core is reserved for overhead. With this configuration and a rack capacity of 20 servers, the expected output is 300Mpps for the entire rack, which costs roughly $55K in CAPEX. A total of five racks would be required to achieve similar output with non-accelerated servers, resulting in a CAPEX of $250K. The bottleneck that causes this cost disparity lies in the performance of the vSwitch. Relying on CPUs for vSwitching tasks limits performance and consumes excessive cores. The Agilio solution eliminate s the dependency, resulting in significant reductions in rack-level TCO.

Test Setup/Tools

The key inputs for calculating TCO for a rack include server and power costs, ToR switch power and costs, and expected output per VM. Assumptions for modeling TCO are vSwitch performance for non-accelerated and Agilio-accelerated OVS. The assumptions in the calculator are derived from rigorous testing done in labs (see Corigine's OVS test plan). The calculator reveals savings based on the CAPEX and OPEX of an accelerated and non-accelerated rack configuration that drives on an expected application output, measured in Packets Per Second (PPS).


Many modern data centers adopt a leaf/spine switching topology, with much of the complex networking tasks such as tunneling and quality of service being pushed to the server. This analysis focuses at the rack-level for this topology. A ToR leaf switch provides 40G connectivity to 20 servers within the rack. Each server uses Open vSwitch to provide VXLAN tunneling and security policies for multiple VMs in each server.


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