V-index - was an online virtualization industry quarterly survey  performed by Vanson Bourne, an independent market research company. It is based on a survey of at least 500 enterprises across the US, UK, France and Germany and is designed to measure 3 parameters – virtualization rate, consolidation ratio and primary hypervisor in use. Results of this survey are performed on a quarterly basis on V-index website.
The significant cost, power and efficiency advantages of virtualization have accelerated its penetration within the enterprise: with this trend comes the potential for all IT infrastructures to become virtual estates. In order to offer a simple yet measurable view of the impact of this technology, Veeam Software developed the V-index, a free resource that is updated every quarter on V-index website. This project is thought to be another source of virtualization market statistics for the virtualization community.
The V-index tracks the penetration of virtualization across the server estates of at least 500 large-scale enterprises across the United States, United Kingdom, France and Germany. The aim is to take an ongoing snapshot of the penetration rate of virtualization and thereby highlight potential trends and issues that affect its progress towards becoming the de facto IT platform.
Organizations are questioned until the required threshold of organizations using virtualization has been reached. This threshold is 200 in the US and 100 in each of the UK, France and Germany. Large enterprises are defined as those with over 1000 employees. The survey takes place over a period of approximately one month: the most recent was performed in Q2 2011 with 544 organizations.