10G Ethernet provides big performance gains for virtualised systems, as long as the network adapter can offload the "heavy lifting" from the host server, said Chelsio Communications as it announced that the latest release 4.1 of Citrix XenServer now includes drivers for its Unified Wire 10G NICs as standard.

The new XenServer release can run twice as many live VMs as before, supports modern multicore AMD processors and 64-bit Linux, and can move and patch virtual machines without downtime - all of which can place additional load on the networking side.

Chelsio claimed that combining its 10G adapters with XenServer provides "the industry's best I/O performance for single or multiple Windows and Linux virtual machines".

It said that its Unified Wire strategy means those adapters also accelerate compute and storage networking protocols, such as iWarp for clustering and iSCSI. In addition, the company recently announced full support for Microsoft's TCP Chimney stack, which allows Windows systems to offload network processing.

An early user of the Chelsio/Xen combination reported that where virtual systems might formerly have been network-constrained, adding 10G Ethernet produced significant gains.

"Chelsio's integrated 10G Ethernet drivers for XenServer 4.1 can substantially boost the network performance of virtualised environments," said Jason Timmins, technical director at UK-based Internet service provider InterLinx. "We can now run even more network-intensive workloads on each virtual machine without sacrificing application performance."

The biggest gain will be in high-throughput applications, said Matt Fairbanks, product marketing VP for XenServer at Citrix. "Our customers can now run their most network-intensive workloads on their virtual servers and achieve the best overall performance in the industry," he claimed.

Citrix said that Xen 4.1 would also include drivers for Mellanox 10Gig adapters. With its background in InfiniBand for clustering applications, Mellanox is now following a similar track to Chelsio. It has shifted over to Ethernet technology and added support for storage networking too - its latest 10G Ethernet adapters offer hardware offload for Fibre Channel over Ethernet (FCoE).