how many vm's we can run in one dell server
hi and welcome to the communities.
Well how many VMs can be hosted on a server is Entirely dependent on the Server configuration. It involves the CPU, memory, storage capacity and of course, the load of the VMs that you are planning to run.
To make this simpler, download the Capacity planning software available for ESXi and it will assist you or, if you have a Virtual Center, the Capacity planning is available in the installer package.
very good question, clarify your question: are you asking theoretically or practically?
Welcome to the Community,
the number of VM's you can run on a single host depends on the physical resources of the host itself and the required/expected performance of the individual VM's. For configuration maximums please take a look at http://www.vmware.com/pdf/vsphere5/r50/vsphere-50-configuration-maximums.pdf
André