How to Downgrade VM Hardware Version

I have often got the question if you can downgrade your Virtual Machine Hardware version from the latest version to a previous version. There is many reasons why you might want to downgrade your VM Hardware Version, but below is few common ones I have heard:

  • VM hardware version you upgraded to is not supported in the vSphere thick client version you are using, this used to be the most common one in vSphere 5.5. Luckily this has dramatically improved in vSphere 6.0.
  • VM hardware version you upgraded to is not supported on older versions hosts that you still keeping or waiting to upgrade.
  • VM hardware version you upgraded to is not supported by your cloud vendor, so you can’t sync your internal VMs/templates to your cloud.

I guess if you had hit this post, you already have a reason of why you want to downgrade your VM Hardware version, so I will not spend too much time on that. Let’s look on how to downgrade VM Hardware Version.

I have to first admit that there is no straight out of the box button that allow you to downgrade your VM Hardware version, unlike when you upgrade it. This might be the reason why when you ask many people about it out there, they will tell you there is no supported way of doing it, but that’s not exactly true.… Read More

Learn Virtualization & VMware vSphere from Scratch

Few months back I got to speak to different friends of mine in the IT field, who were specialized in networking, storage, SAP, Database, Hardware and so on. I was surprised they had zero to little exposure to Virtualization although they are well versed into their field of expertise. They even held highest certifications in their fields like CCIE & the equivalent for the different specialty. This has kinda surprised me as working with Virtualization/Cloud Admins on daily basis, I had thought most IT professional by now are well versed with Virtualization. This has proved being far from the true, the more I speak to IT Professionals outside the Virtualization field.

Figuring out that many IT Professionals are still stuck in the past within the physical infrastructure, I decided to explore the cause and try to help improve the situation. Asking my friends about the cause of not catching up on Virtualization although they are aware its rapidly changing every IT field. I asked my networking friends if they are already aware that there is more virtual network ports than there is physical these days and they were surprised of that fact. I asked them what will they do when 90% of the network ports become virtual network ports and a part of a virtual switch.… Read More

vCloud Director joining VMs to specific Active Directory Domain OU

While VMware vCloud Director 1.5.1 has a lot of flexibility, one thing it seems missing is getting VMs to join a specific OU in Active Directory Domain. Making your vApps VMs join a particular domain is quite easy using the vCloud Director web interface. All you have to do is to configure your domain information in your vCD, then configure the join domain parameters as showing in the below screenshot.

vCloud Director Guest customization joining AD
While configuring vCD to a level where it get vAPP VMs to join a specific Active Directory Domain is a straight forward task, getting those vAPP VMs to join in a specific OU require a bit more work and can be challenging for a first time vCD user. Actually vCD 1.5.1 does not have that capability out of the box by just using the web interface, but you will have to integrate it with vCO or create your own domain joining script.

Note: This has changed in vCD 5.1 & now you can do it directly from the GUI though if you still using vCD 1.5.x then please utilize the instruction below.

While many admins will panic when they hear that they have to create their script, in this scenario its easy enough that every one should be able to complete the task in less than 10 minutes.… Read More

Virtual Machines vDS Network Interfaces configuration in VMX file is lost upon removing it from inventory

Note: This is no longer an issue in vSphere 5.1.

Today while doing a manual DR failback test at one of the customers sites where they use Virtual Distributed Switches, I have noticed when removing/adding a Virtual Machine to inventory it lose the configuration for its network interface of which port group its connected to and the like. As the customer was running vSphere 4.1u1, I went ahead and tested the same in my lab running vSphere 5.0  which end up  having the exact same behavior. Its important to note that this behavior only affect Virtual Machines that is connected to a Distributed Switch port group, & it does not affect port group configuration for Standard Switches. This behavior although look odd seems to be nothing but as intended by engineering as it makes the assumption that you are restoring the VM to a different Infrastructure where these Distributed Switches might not exist.

Agree or not agree is not the purpose of this post, but to confirm this behavior as well to be in front warning that you should keep that configuration handy before hand in case you need for any reason to remove your VMs from inventory. In my case was carrying out a manual disaster recovery fallback without involving vCenter Site Recovery Manager.… Read More

Tolly Common Test Plan for Virtual Server Performance

I have been contacted by Kevin Tolly the founder of to evaluate their Virtual Server Performance Test Plan & provide suggestions in that regard about two weeks ago. Kevin & his team were kind enough to provide me with a one year license to their Virtual Server Performance Test Plan Document for my own personal use without any string attached. I believe they are offering the same to many other Virtualization Experts around the globe in order to improve their document & get some honest feed backs from professionals who hit the virtualization field on daily basis. Below is my honest review & thoughts of the document.

As no product is ever perfect and Tolly Common Test Plan for Virtual Server Performance is no exception for that I will cover the points I like & the points I believe are missing of the report in here.

I will start with what I like about the Tolly Common Test Plan for Virtual Server Performance. The document is focused on helping IT Professionals in identifying the key concepts for virtual servers benchmarking as well helping in avoiding common mistakes in virtual servers benchmarking. Its one of these topics that has barely any standards & many misleading concepts are all over the place, that make a similar document essential for enterprise environment that is evaluating multiple virtualization solutions.… Read More

VMware vSphere Virtual Machine still show old datastore after storage vMotion

Before I start with the article, I have to point out this is not a VMware bug. Its the VMware admins doing what they are not suppose to do. VMware ESX 3 & VMware ESX 4 Administration Guides mention clearly that you should not VMotion or Storage vMotion a Virtual machine before disconnecting it from CD Media & ISO images that is only available to the first host or Datastore. Actually it will even warn you when you trying to do that.

That has been said, I still have a good number of customers who call me about their Virtual Machine summary still showing that it has a disk on the old datastore after Storage VMotion it to a new datastore. In most cases, it end up that the customer has carried out a Storage VMotion on a virtual machine that is connected to an ISO Image on the old datastore (probably where they have installed the VM from) see the image below.

ISO Image from the original Datastore attached to VM

Luckily the solution is quite easy, all you have to do is just change the Virtual Machine CDRom setting to Client Device & Hit OK as per the image below:

changing Virtual Machine CDRom Settings to client Device

Now you should only see the new Datastore in your Virtual Machine.… Read More

Resizing a virtual disk with VMware

The other day, an old virtual machine of mine with VMware (that I sometimes used to test various configurations, cases, applications, etc.) ran out of disk space since it had only 2GB for storage! By today’s standards, 2GB of storage seems like a joke! But anyways, I had to solve this inconvenient problem or else I would lose time creating a new virtual machine and configuring the operating system from scratch according to the new specifications for virtual disks.

VMware provides a set of line-of-command utilities to support the administration of virtual machines. Among them is a utility called vmware-vdiskmanager that makes this operation much simpler. Simply run the command with the “-x” option and the desired new size for the virtual disk and…problem solved.

For example:

$ Vmware-vdiskmanager -x 5GB virtual_disk.vmdk

Well, the task seemed simple, but the “virtual disk manager” (a.k.a. vmware-vdiskmanager)refused to perform this operation, signalling that you cannot perform such an operation on disks that use or have used snapshots. The message appeared as follows:

This disk is part of a snapshot chain in ‘/var/lib/vmware/Virtual Machines/vm1/SO.vmx’.
The selected operation can only be executed on a disk with no snapshots.

A question came to me almost immediately: how we get rid of snapshots?… Read More