What is the maximum number of vCPUs a VM can have?

The maximum number of virtual CPUs (vCPUs) that a virtual machine (VM) can have directly correlates with the number of logical CPUs present on the host system. In the context of VMware vSphere, each vCPU is essentially a representation of a logical processor on the physical host. Thus, the limitation comes from the hardware capacity of the host, specifically how many logical processors it has available.

As the virtualization platform uses the host's CPU resources to allocate processing power to virtual machines, a VM can only be assigned a number of vCPUs up to the total logical CPUs available on that host. Additionally, this setup ensures optimal resource allocation and performance, as overcommitting vCPUs beyond the available logical CPUs may lead to contention and decreased performance.

Contrastingly, claiming that the maximum number of vCPUs is unlimited is inaccurate, as there are always physical limits imposed by the underlying hardware. Similarly, designating a fixed number, like 16 or 32, does not reflect the scalable nature of modern processors that can have varying numbers of cores and threads. Therefore, the correct understanding revolves around the capability of the host's total available logical CPUs defining the limits for vCPU allocation within the VMs.