Microsoft may have been late to the server virtualisation party, but it’s Hyper-V beginning to see success up against the more established VMware and Xen hypervisors.
"Software services were not restarting when we restarted the server," Holman told TechWorld.
Expressnet then investigated VMware and Xen, but "wasn’t overly convinced" at the suitability of those products either.
When Hyper-V came out as part of Windows Server 2008, Holman was impressed with the beta version of it.
"We rolled out a Dell server as a test bed for Hyper-V and we were testing virtualisation from a customer product offering point of view and for our own systems," he said.
The trial was successful and Expressnet went into production and now has customers looking for virtual dedicated servers.
"Customers are happy with performance and its even taken me by surprise," Holman said, adding another server is now being brought online for virtual machines.
The hardware is Dell 2950 servers with two quad-core Xeon processors and 16GB and 32GB of memory, respectively.
The 16GB machine is running 12 VMs and it is anticipated the 32GB machine will run 20 VMs.
Holman said one of the restricting factors of Hyper-V is that it pre-allocates RAM so as soon as the VM is started it allocates the memory to a particular VM and can’t be changed without a re-configuration and reboot.
"Xen and VMware can do that but the performance benefit we are getting outweighs that," he said. "The shut down and boot times are faster in virtual environment and only takes about 40 seconds."
Holman said Hyper-V is lacking in management tools; however, Microsoft has released the its System Centre VM Manager which makes it easier to do advances features like cloning VMs and templating.
"The performance monitoring we did was fairly loose. We ran Xen 4.1 and ESX 3.5 on two boxes with 2GB of RAM and it was more of a gut-feel scenario than proper benchmarking. We found VMware and Xen was the slowest."
Expressnet also leaned towards Hyper-V as a result of legal uncertainty with hosted VMs on VMware.
"In the terms and conditions it was a bit ambiguous whether you can offer the product how we wanted with the base-level ESX server," Holman said. "But that was a secondary concern. We were looking at performance and cost."
Holman also praised the "point-and-click" installation of Hyper-V on Windows Server 2008 data centre edition, which took about 20 minutes. But the virtual network adapters had to be set up manually.
The data centre edition of Server 2008 allows unlimited VMs to be hosted on the physical machine.
The guest operating systems are Windows Server 2008 as it was unclear of Microsoft’s Windows Server 2003 licence allowed migration of a physical system to a virtual one.
Holman has been trying to get a hold of Microsoft’s Linux integration tools for Hyper-V for some compatibility testing, but "they seem exceptionally hard to find".
"Virtualising saves me a lot of time and resources and we’re using less power and servers," he said.