Originally Posted by
Norphy
Not quite right. You can run as many machines as you like on the Hyper-V server but with one Windows 2008 Enterprise licence, you're only licenced to run 4 virtual instances of Windows 2008 Standard or Enterprise on that box. You can buy another Windows 2008 Enterprise license and run an additional four and/or run as many other non-Windows OSeseseseses as you're licensed for on there too.
We have a VMware vSphere farm set up here. It consists of two clusters. Cluster 1 has five Dell PE 2950 servers with dual quad-core Xeon CPUs and 32GB RAM. They're all attached to two Equallogic SANs and have about 9TB of storage available to them. Each server has four 1GB connections to the iSCSI fabric, 1 10GBe connection to the network backbone, 1 1GBe connection to the network backbone for the service port, 1 connection to a seperate network for vMotion and one 1GBe connection to our DMZ.
Cluster B has three PE M910 servers in them which have 4 quad-core Xeon CPUs and 64GB RAM each. That's attached to another Equallogic SAN with about 4TB of available storage. They have a similar amount of network connections to the servers in Cluster A but have the four 1GBe iSCSI connections replaced with a single 10GBe connection.
Of course, it all depends on how much you have to spend but if you're serious about setting up a robust virtualisation farm, a setup similar to this is a good bet. Three servers with eight cores and 32GB RAM each would probably be enough plus an iSCSI SAN with as much storage as you can afford. A setup like that will give you good redunancy and high availability. If one of your hosts goes down, there ought to be enough capacity in the other two to make sure you don't lose any services. If you go the HyperV route, make sure you get SCVMM (Systems Center Virtual Machine Manager) to make this automated. I'd also say that if you go the iSCSI route, make sure you don't plug the iSCSI ports into your core network, even if you VLAN it off. A lot of traffic is generated by iSCSI and your switch may not have the capacity to cope. Install a seperate iSCSI switch.