To try to counter this perception, Microsoft has just released some results detailing performance capabilities of Hyper-V.
Significant Performance with Hyper-V: The performance, scalability, and low overhead of Hyper-V can be used to reduce costs and improve the manageability, flexibility, and availability of consolidated Microsoft server applications. 3rd party testing by research firm ESG of Hyper-V running Microsoft server applications indicate the following:
"Exchange Server 2010 scaled to 20,000 mailboxes on a single physical server, across four VMs, with extrapolation to 32,000 mailboxes.
SQL Server 2008 R2 showed performance of a single VM within 88% of a physical server and scaled to 1,800 OLTP transactions per second.
SharePoint Server 2010 scaled to over 450,000 users across five VMs and showed linear scalability from 1 to 3 VMs."
All terribly impressive, but you have to know what the hardware and infrastructure was. According to the PDF file describing the testing at Enterprise Strategy Group Lab Summary on Hyper-V R2 SP1 Application Workload Performance. The hardware was as follows:
Servers
An HP BL680C blade server was used to test Exchange 2010, SQL Server 2008 R2, and SharePoint 2010 application workloads virtualized with Hyper-V R2 SP1. Each server blade was populated with up to 24 processor cores and 128 GB of RAM. Microsoft Windows 2008 R2 SP1 Data Center Edition was installed on a pair of mirrored internal drives in each blade.
Storage
The blade server chassis was Fibre Channel SAN attached to an EMC CX4- 960 disk array. Each of the servers had a pair of 4 Gbps Fibre Channel connections to the disk array. PowerPath version 5.2 was used for a multi-path connection between the servers and the disk array.
The disk array was populated with 155 15K RPM FC disk drives. Wide-striped RAID-10 pools were used to store virtualized application data, log data, operating system images, and application images. The application data pool was configured over 88 drives. Up to eight 700 GB data LUNs were configured and presented to each virtualized application server. All of the storage used by Hyper-V R2 SP1 virtual machines was configured as fixed virtual hard drives."
I think a polite cough is allowed at this point. Although this hardware is available and shipping, and certainly brings me out in a tingly sensation, it is not exactly typical of any sort of hardware that most companies use most of the time.
As always, headline benchmark figures can look terribly impressive. There is no doubt that HyperV can take on huge loads, especially if it is sitting on top of monster hardware.
