VSphere | Advanced snapshot trobuleshooting - Part 3 - Example: Invalid snapshot configuration

Unable to consolidate because of invalid snapshot configuration

This is Part 3 of the short tutorial series:
vSphere | Advanced snapshot troubleshooting

This is much more advanced than our previous example.  You will see these two errors if you attempt to consolidate, clone or migrate the VM:

Detected and invalid snapshot configuration

or

... vmdk was not found

VSphere | Advanced snapshot trobuleshooting - Part 2 - Example: Unable to consolidate because the file is locked

This is Part 2 of the short tutorial series:
vSphere | Advanced snapshot troubleshooting

Virtual Machine consolidation attempts result with bellow error:
Unable to access file since it is locked

VSphere | Advanced snapshot trobuleshooting - Part 1 - The ESXi shell is your friend

I am writing this article as an extension to my previous post A VM is showing disk size of 0B where I will attempt to make a general explanation on how to troubleshoot and successfully solve snapshots and consolidation problems in your vSphere with a number of examples. Because the general article was so big, I decided to split it into three parts. This Part 1, is where I am describing the commands which are used to solve most of the snapshot problems and in the next two parts I will describe the process of troubleshooting via examples.

CentOS V2V | Hyper-V to VMware - The easy way

I had a task to export a Hyper-V, CentOS 6 VM and deploy it to a vSphere cluster. Due to the nature of the VM we had to preserve it because the VM was already set up and it was too long for us to build a new one with the same settings.

Before start I would like to point out that if this is a Linux VM you are doing, then because there will be a complete hardware change you may end up with unbootable clone, which can be fixed. This did not happen to me though, but in the end of this article I will also point those things out as potential issues.

vSphere | A VM is showing disk size of 0B

Being given a task to figure out and clean up the mess of a poorly maintained vSphere Infrastructure a while ago, i encountered a very strange problem.

They informed me that the Veeam Backup failed for that VM, and the error message was:

Virtual disk configuration change detected, resetting CBT failed Details: A general system error occurred: 
Creating VM snapshot
Error: A general system error occurred: 

Virtualizing CentOS 5 physical servers with LVM configuration

Somewhere on the internet was written:

Virtualizing a physical Linux server is a combination of knowledge, experience and luck.

Recently I had a the task for a client to virtualize a CentOS 5 Linux server. After searching on Google about it, I was disappointed to see so many posts of people having problems with it, especially those who had physical Linux servers with LVM configurations. If you research about a bit, you will be surprised on how many production CentOS 5 servers exist which run with their default installations with one large physical volume and one swap partition. The things are even worse if the boot partition is also on that same logical volume.

Unfortunately there are still many forgotten production Linux servers today which run CentOS 5. The things are even worse, because in smaller companies, those servers are set up and forgotten, and even those admins who once administered those servers are gone and not working for that company for years. What happens is when you try to virtualize Linux server with similar configuration described above with the VMware converter, the process usually terminates at 97% with error:

FAILED: An error occurred during the conversion:

'Partition number must be set for the boot volume'

Another common example is also found in this VMware KB article.

When you try to power on this crippled VM you'll end up with one of the two things.

1. The VM will behave as it is an empty VM (just created with no OS)
2. The system will try to boot, you will see the GRUB loading screen, and after a while when the kernel starts you will see a kernel panic message.

Both of this problems are completely solvable. Since you already have the main volume with everything inside (databases, software etc..) you just need to make sure that now you have to repair the  key parts from which every Linux operates boots and operates - the boot partition.