You do not need to have a physical server. Tableau server can be used in Virtual machine.
For Tableau Server 9.3 on a 64-bit virtual machine, you need a minimum of 4 physical cores. If you are installing on an Amazon EC2 instance, this means 8 vCPUs.
All Tableau products operate in virtualized environments when they are configured with the proper underlying Windows operating system and minimum hardware requirements. Tableau recommend VM deployments with dedicated CPU affinity.
The minimum of 4 physical cores is only suggested for prototyping and testing of Tableau Server. The minimum configuration recommended for production usage of Tableau Server is based on these hardware specifications (Single computer):
8 physical cores, 2.0 GHz or higher CPU
32 GB system memory
50 GB minimum free disk space
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