Well over one-third (38.9%) of all servers within all of the enterprises surveyed were virtual and 86.5% of all enterprises are using virtualisation to some degree, according to Veeam Software V-Index for the third quarter of 2011.

Enterprises believe that each of their physical hosts is hosting nine virtual machines on average; however, by calculating the ratio of virtual machines to physical hosts for each individual enterprise, the actual average consolidation ratio comes to just 5:1, the report said.

Of the enterprises using server virtualisation, 84% use VMware, 43% use Microsoft Hyper-V, 53% use Citrix Xen, and 16% use other hypervisors, while of the enterprises using desktop virtualisation 75% use VMware, 45% use Microsoft Hyper-V, 56% use Citrix, and 7% use other hypervisors.

The survey also revealed that 38% of enterprises using server virtualisation, and 34% of those using desktop virtualisation, intend to change their primary hypervisor over the next 12 months.

Concerns around costs; licensing models; and the features and maturity that other hypervisors can offer are the main concerns driving this for both types of virtualisation.

Among the enterprises surveyed, 36% cited concerns about reliability, 34% cited concerns around application performance, 33% cited concerns around backup and restoration, 32% cited the need to wait for a hardware refresh before deployment, and 31% cited concerns around managing the virtual estate, all as barriers to increased virtualisation penetration.

The survey also found that 81% of enterprises using virtualisation expect to see their virtualised server estate to increase in the next 12 months.