Hot Add and "Need have have"

One of the new features that were added to ESX4 is Hot-Add. What this feature does it allows you to add additional RAM or vCPU to your VM (if the operating System supports it)

Like any good vAdmin - I have upgraded my personal ESX box to Version 4. This is a whitebox with ESX3i installed.

Upgrade process was pretty simple as you can see in this previous post.

So if you noticed in my previous post after installing your license is a 60-day Evaluation with all the bells and whistles like below

The option of ESX4i - Free version - is available for up to 999 CPU’s all you have to do is just ask.


So I requested a license key and after receiving the mail from VMware I proceeded to enter my license. Now we all knew that when entering the free license key in ESX3i you lost some functionality - like VCB - Virtual Center Agent etc. But for ESX 4i when changing the license - You lose a lot more in comparison - and I was shocked to find out how much.



One of the wonderful things you can do with ESX VM’s is resize the VMDK’s - it is a simple

vmkfstools -X 30G /<…..path to …. >.vmdk

And voila your vmdk just grew to the size you asked it to. So now you boot up your VM (for arguments sake - let’s say it is a Windows 2003 Server) and you now have the extra space but in this case this was the system volume which cannot be extended while the system is live.

So the solution to this one is:

  • Extend the volume
  • Add the vmdk to a running Windows 2003 Server (while it is powered on)
  • diskpart
  • rescan
  • select disk 1 (of course the number may vary)
  • select partition 1 (same as above)
  • extend
  • Power off of this VM
  • Remove the disk
  • Power on the first VM again and hey presto you have a full partition including the extended space you just created.

Now this is all fine and wonderful - and it all relies on the fact that we expect that we can add resources to a running machine (namely HD / NIC - those are the ones that I use the most). This can be used in a large amount of scenarios - such as the one I had today - I had a lock on a file that I just could not get rid of. So I tried to do the same thing:

  • Power off the VM
  • Add the VMDK to another running machine
  • remove the lock
  • but … hold on I could not !

I ran into this error:


ESX claims that I am trying to hot add a resource - which in all honesty is completely true.
I was. A vmdk.

So i wanted to check was this connected to the serial number I just changed before hand. So of course changing the license back to evaluation version I could add the hard disk without any issue. So I changed the license back and tried the same with adding a network card.

And yep you guessed correctly - same error message.

  1. The error message of course is not very well phrased - and I would love to know what “need have have” is?
  2. Why in heaven’s name would you take away the most basic functionality that has been in every single VMware product (besides Player) for the past 5 years? VMware? Please tell me that was a mistake?

Update 30/05/2009

I have started a thread on the VMTN forum with this question but have as yet to hear any concrete response from VMware. The only shocking thing I found that if this is a licensing issue - then we are all in for a bigger surprise! The minimum, license level that you use Hot-Add is Advanced.

How do you like them apples?