Abstract: A data center has several dis-aggregated data clusters that connect to the Internet through a firewall and load-balancer. Each dis-aggregated data cluster has several dis-aggregated compute/switch/disk chassis that are connected together by a mesh of Ethernet links. Each dis-aggregated compute/switch/disk chassis has many processing nodes, disk nodes, and I/O nodes on node cards that are inserted into the chassis. These node cards are connected together by a direct interconnect fabric. Using the direct interconnect fabric, remote I/O and disk nodes appear to the operating system to be located on the local processor's own peripheral bus. A virtual Ethernet controller and a virtual generic peripheral act as virtual endpoints for the local processor's peripheral bus. I/O and disk node peripherals are virtualized by hardware without software drivers. Rack and aggregation Ethernet switches are eliminated using the direct interconnect fabric, which provides a flatter, dis-aggregated hierarchy.