Resource management

Virtual CPU
a VM can have up to 128vCPU
Hyper Threading 
-can execute  2 threads at the same time on each physical CPU
-is  enabled  at host level on BIOS ( also called  Logical Processor)
- to check if it's enabled  on VMware WebClient go to Host->Summary tab-> CPU under Hardware

Example:
8 physical cores, HT disabled -> 8 logical cores ( you can assign 8 vCPU in VMware)
8 physical cores, HT enabled -> 8x2=16 logical cores ( you can assign 16 vCPU in VMware

Virtual memory
The total configured memory size of all  VMs might exceed the amount of physical memory from the host
Example:
you can have a host with 2GB physical memory and run 4VMs with 1Gb memory each
* if all 4 VMs are actively consuming memory the host can  become overcommited--> no new VMs can start ( the already powered on machines are not affeced)

Resource ( CPU, memory, storage I/O allocations) management:
to control access of a VM to resources you need to configure this:
Shares: the relative priority  or importance of a VMs access to resource
             you can add shares to a VM while it is running
             when you delete or power off a VM the number of total shares decreases
Limit: Consumption of resource cannot exceed  this value
Rezervation: this value of resource has to be available to  the VM in order to start

Example:

Engineering pool 1000/(1000+2000)=1/3= 33% resources
Finance pool 2000/(1000+2000)= 2/3=66% resources
Eng-Test VM: 1000/(1000+2000) from 33%=  1/3*1/3=11% from total resources
Eng-Prod VM: 2000/(1000+2000) from 33%= 2/3*1/3= 22% from total resources