Microsoft Hyper-V 3.0 addresses the hardware and memory limitations of Hyper-V R2 with virtualization scalability improvements to the host, virtual machine and cluster levels.
Previewed at the Microsoft Build conference in September, Hyper-V 3.0 will also feature native network interface card (NIC) teaming and non-uniform memory access (NUMA) support, both of which allow large-scale virtual infrastructures to achieve greater performance levels.
Here’s a breakdown of Hyper-V 3.0’s extensive virtualization scalability improvements.
Host scalability, clustering and new hardware support
Microsoft Hyper-V 3.0 hosts will support a whopping 160 logical processors and 2 TB of memory. Presently, Hyper-V R2 supports only 64 logical processors and 1 TB of RAM, even though most servers today don’t approach that size. But it’s only a matter of time before server hardware outgrows Hyper-V R2’s limitations.
The maximum number of virtual machines (VMs) that a Hyper-V host can run will also dramatically increase, but Microsoft has yet to specify an exact number. Presently, Hyper-V allows for up to 384 virtual machines to reside on a host. (I think it’s conceivable that a Hyper-V 3.0 host will support up to 1,000 VMs.)
These virtualization scalability improvements also extend to the cluster. Microsoft Hyper-V 3.0 will support up to 63 nodes, and Hyper-V 3.0 clusters will now support up to 4,000 virtual machines. In contrast, Hyper-V R2 clusters support up to 16 nodes and 1,000 virtual machines -- as long as a single node doesn’t contains more than 384 VMs.
Clearly, Microsoft has made drastic changes to the hypervisor, but harnessing these virtualization scalability improvements ultimately comes down to hardware support. With that in mind, Microsoft will introduce two new features that should help server hardware accommodate large groups of virtual machines.
The first of these features is native NIC teaming, which allows combining multiple NICs to provide more bandwidth to host servers. In Hyper-V R2, NIC teaming is possible with expensive, proprietary products. But in Hyper-V 3.0, NIC teaming will be an OS level feature, meaning administrators can mix and match hardware from different vendors, thus driving down costs.
Hyper-V 3.0 will also include guest NUMA support. NUMA is a type of memory that exists in newer servers. The memory is divided into NUMA nodes, which are allocated to individual CPU cores. When configuring a VM, it will be possible to assign specific CPU cores to their corresponding NUMA nodes, which should equate much better performance.
Virtual machine scalability improvements
In addition to the tremendous host- and cluster-scalability changes, Microsoft also made virtual machine-related improvements.
Presently, Hyper-V VMs can use up to four virtual processors and 64 GB of RAM, but a Hyper-V 3.0 virtual machine will support 32 virtual processors and 512 GB of memory. However, the VM’s operating system will often limit the amount of virtual processors that you can allocate to a VM.)
One of the most significant Hyper-V 3.0 changes is the new VHDX virtual hard disk file. Its biggest advantage is that it supports 16 TB virtual hard disks -- as opposed to the current virtual hard disk format, which has a 2 TB limit. Recently, this 2 TB threshold has become an issue for larger organizations.
As you can see, Microsoft Hyper-V 3.0 stands to offer much better virtualization scalability than the current version. In theory, this should enable greater consolidation ratios and virtualization of more mission critical applications.
This was first published in November 2011