Microsoft To Speed Hyper-V With Release 2 Of Windows Server 2008

Microsoft will add advanced network messaging to its Hyper-V hypervisor, overcoming a known bottleneck, when it issues Release 2 of Windows Server 2008 at the end of the year. The enhancement is significant because dealing with network traffic is a bottleneck in all hypervisors.

As use of VMware's ESX Server has grown, the bottleneck has shown up on servers hosting virtual machines with network-intensive traffic. VMware cooperated with Cisco to solve the problem, and Cisco plunged into blade servers with its Unified Computing System in the belief it had at least a temporary lead over other manufacturers in producing blades optimized for running virtual machines.

But Jeff Woolsey, Microsoft's lead program manager for Windows Server 2008 virtualization, said at the TechEd show in Los Angeles on Monday that his company has been focused on the same problem. Before the year is out, it will offer its own low-cost solution -- compared with the Cisco/VMware collaboration -- in the updated version of Hyper-V, now part of Windows Server 2008.

The competition between VMware and Microsoft is thus heating up, as Microsoft claims rapid gains in virtual machine implementation based on Hyper-V. At an unexpectedly early date, Microsoft is trying to come up with its own advance for the market leader's best innovation so far this year. "We've had 750,000 downloads since Hyper-V was introduced seven months ago. It's being adopted especially fast in education and small business," Woolsey said in an interview at the end of TechEd's opening day. About 7,000 Windows Server and Microsoft .Net users and developers attended the show.

One difference: Cisco's UCS combined with VMware's vSphere 4 handles converged network traffic at 10 Gigabit Ethernet speeds, whether that traffic is headed for an Ethernet network or Fibre Channel storage.

Microsoft's solution will address the Ethernet network traffic problem only. Hyper-V users who want to make use of Fibre Channel storage can equip their servers with Fibre Channel network adapters and still use the high-speed storage network, if they choose to, Woolsey said. Another difference is that Hyper-V will fit easily into either a 1 Gigabit or 10 Gigabit Ethernet network. Cisco's Unified Computing System, on the other hand, moves its users beyond the 1-Gb structure into 10-Gb Ethernet. That may mean some virtualization users who are not yet ready to invest in 10-Gb Ethernet gear can get performance gains they want with Hyper-V -- and move to 10-Gb devices later. "That puts Hyper-V and VMQueue is in a great position for the transition to 10 Gigabit Ethernet, when it comes," Woolsey said.

VMQueue is a substitute in Hyper-V for the software switch. It can recognize which virtual machine incoming network traffic is intended for and route it directly to that VM. "VMQueue allows me to copy that traffic directly from the network adapter to the virtual machine's TCP/IP network stack," without intermediate software switching, Woolsey said. Likewise, outgoing traffic gets moved from the VM directly to the network adapter card and out to the network, also without a switch.

VMQueue assesses the virtual machine network traffic while it's waiting in a queue. At the same time it knows which virtual machine is connected to which network adapter. It knows when a channel is needed to move traffic, and where among the physical devices that channel is located, Woolsey said.

In addition, Hyper-V will support jumbo Ethernet frames, which carry up to 9,000 bytes instead of 1,500, which results in many fewer interruptions by network traffic of the hypervisor's application processing. "With jumbo frames, everybody gets the benefit, even 1 Gigabit Ethernet," said Woolsey.

In yet another networking adaption, Windows Server 2008 late this year will support Chimney, or a way for Windows Server to intervene at the prospect of TCP/IP network traffic arising in a virtual machine and off-load it from the VM and physical server through the network adapter card to a TOE or TCP/IP offload engine, a hardware device external to the server. The shift saves up to 80% of CPU cycles formerly devoted to handling TCP/IP traffic.

These three additions to Windows Server 2008 and Hyper-V are intended to allow more "balanced" configuration of virtual machines. As the number of virtual machines builds up per physical server, network I/O is more and more likely to emerge as a bottleneck. Release 2 of Windows Server 2008 seeks to relieve that bottleneck before it slows Microsoft's customers increasing reliance on VMs to carry their workloads, said Woolsey.

Learn more about all the latest products and technologies at TechWeb's Interop Las Vegas, May 17-21. Join us (registration required).