Multicore servers allow organizations to consolidate 20 or more production servers into each virtual server host, saving space, power, and staff resources in the process. But feeding these servers enough I/O bandwidth has become a major headache for many data centers.

Some experts recommend Gigabit Ethernet connections for each processor core on the host to ensure sufficient bandwidth, dedicated connections for management and virtual machine migration, plus additional Fibre Channel or Gigabit Ethernet connections for storage, resulting in cable and switch port sprawl.

Leading vendors, including many Fibre Channel providers, are pushing enhanced 10-Gbps Ethernet with Fibre Channel over Ethernet (FCoE) as the solution. Granted, 10-Gbps Ethernet addresses the bandwidth issue, and FCoE converged network adapters can handle the storage side of the equation. However, the standards for both FCoE and Date Center Bridging, the IEEE name for the Ethernet enhancements FCoE requires, haven't yet been ratified.

Other vendors have proposed solutions to the virtual server I/O problem that could be more cost-effective and flexible. These systems create multiple virtual-aware adapters (virtual network interface cards and virtual host bus adapters) assigned to virtual machines. As the VMs migrate from host to host, the virtual NICs and virtual HBAs let them keep their MAC address or World Wide Name, alleviating some network security and zoning issues of VMs.

Virtualization-aware I/O devices' support for quality of service means that virtual NICs and HBAs supporting critical or latency-sensitive applications can use reserved bandwidth and take higher priority than users surfing Facebook while sharing a single physical connection.