What is the plural of VM (Virtual Machine)?

The conclusion of this article is that VMs is the correct form.

I suspect in some sentence circumstances VM might possibly be used as plural too, but not preferred.  So far, I have not found a proper sentence in which usage of VM as plural is correct without doubt or argument against it.  Usage of VMs as plural form would always be correct and safest usage, and removes confusion. 

Note that this article is specifically for the abbreviation VM that represents the phrase Virtual Machine, and NOT any other phrase.  However, same logic and grammar rules shown below apply to any other phrase that has the abbreviation of VM, IF that phrase's plural form involves ONLY the adding of the letter s to make it's singular form become plural.  Before someone mentions it, yes, I can see how VMs could get confused with other abbreviations that are VMS.

The below will break down the various considerations based on the Amglish (American English/US language/American language), and English language (British English/British Language/England language). :) 

• VM = Virtual Machine (Example Sentences = Microsoft Virtual PC is an virtual machine.  Microsoft Windows Virtual PC is a VM.  This virtual machine is free.  This VM is free.)
  
  
• VM's = Virtual Machine's (Example Sentence = This is the virtual machine's core code.  This is the VM's core code.)
  
  
• VMs = Virtual Machines (Example Sentence = There are many virtual machines in the world; such as Virtualbox, OpenVZ,  VMware, vSphere, Azure HyperV, and dozens more.  There are many VMs in the world.)
  
  
• VMs' = Virtual Machines' (Example Sentence = These virtual machines' processing ability is relative to the hardware memory allocation to each.  These VMs' processing ability is relative to the hardware memory allocation to each.)
  
  
• VMes = Simply wrong.  Expanded, this would become Virtual Machinees, and that is wrong spelling.

In case you have seen usage of VMes, then know that was not for the plural of the phrase Virtual Machine, and if you saw a VMes meant to represent Virtual Machines, then that was wrong usage as explained above.  It is incorrect to use VMes for Virtual Machines.

VM's references something belonging to a single virtual machine.

VMs would correctly reflect proper grammar for a plural abbreviation of virtual machines. 

VMs' references something associated with or belonging to a group of virtual machines.

In case someone is actually considering VM'es, then know that this is very wrong.  VM'es = Virtual Machine'es.  Does not make sense.  VM is not a stand alone word, but an abbreviation (specifically an initialism).  The abbreviation in consideration here is VM, and it is not the same as a word of vm or name or Vm.