What is the difference between VMware ESXi and VMware Server?
VMware ESXi is an enterprise-class hypervisor that offers a bare-metal architecture for near-native performance, features like memory de-duplication to increase consolidation ratios and a cluster file system for managing VM files on shared storage. VMware ESXi and VMware ESX are the critical foundations for a dynamic and flexible virtual infrastructure. VMware Server installs as an application on Windows or Linux, relying on the operating system for resource management. This limits the performance and scalability. VMware Server is popular for test and development activities. Virtual machines created using VMware Server can run on VMware ESXi, but they must first be converted using the free VMware Converter.