The fabric of the Private Cloud is made up of Compute, Storage and Network resources – each of these combine to create an infrastructure which has the following characteristics – self-service, resource pooling, elasticity, chargeback and specific to private cloud, two additional – customisation and control. Private Cloud is seen as the next level of server virtualization– which is typically deployed in organizations to consolidate their existing physical server infrastructure.
The leader in server virtualisation today is VMware, followed by Microsoft and Citrix. VMware ESX has been around for over 10 years with VMware releasing their latest iteration vSphere 5.0 last year. Microsoft currently has Hyper-V as a server role in their Windows 2008 R2 OS and Citrix have their Xen-based hypervisor – XenServer. Today all 3 hypervisors provide a solid foundation for building the compute resource of the Private Cloud with features and capabilities such as live migration, high availability, scalable clusters and dynamic optimisation. Thus, the differentiating factors are then in regards to scalability, workload support and licensing costs. Current Citrix and VMware hypervisors have the edge over Hyper-V in terms of hardware and guest workload support with both hypervisors supporting 160 logical processor and guest virtual machine support of up to 32 vCPUs, combined with the fact that both support many more Linux distributions than Hyper-V. However, Hyper-V does have an edge in licensing and cost - where usage rights for Windows licenses means that Hyper-V is literally free when running mainly Windows workloads. For example – Windows 2008 R2 Datacenter edition allows unlimited VM usage rights which means a host licensed by this will enjoy unlimited number of VMs running Windows Server OS – this is regardless of which hypervisor the host is running. Since most workloads virtualised today are Windows OS and since Hyper-V is just a role within Windows then there is no cost associated with the hypervisor unlike Citrix and VMware.
While some enterprises seem to be more concerned about what hypervisor they select to build their private cloud on – it really is the management piece that they should be concerned with. Citrix with their tool XenCenter is hardly enterprise-ready and VMware with their tool vCenter and Cloud vCloud Director only manages VMware products and is expensive. For heterogeneous hypervisor support the product from Microsoft – System Center Virtual Machine Manager 2012 supports all three hypervisors mentioned above. It enables the ability to pool these hypervisor resources to create Private Clouds – which is an abstraction of overall compute capacity with quotas assigned to specific groups of users or departments. As a tool for creating and managing private cloud – this tool stands head and shoulders above the rest, as well as being cost effective to license.
Lastly, Microsoft is catching up with the other two vendors with the pending release of their Windows 8 Server which includes an updated and improved version of Hyper-V which meets or if not, exceeds all the scalability limits that vSphere and XenServer have today. Microsoft has also announced that Hyper-V will be included as part of every Windows 8 OS from consumer to server editions. This reminds me of the web browser wars back in the late 1990s when Microsoft started bundling Internet Explorer with the operating system. Back then Microsoft’s market share in the browser market was literally 0% and within the space of 4 years it jumped to 80% – as they say history has a strange way of repeating itself.