VMware vCenter Converter is a free tool that is an indispensable utility for VMware administrators. Even now, many years after physical to virtual (P2V) conversion in many enterprises has finished, there are systems to convert or reconfigure, as the tool can also optimize and resize disks and their layout.

VMware vCenter Converter can not only do P2V but also Virtual to virtual (V2V) conversions.

V2V migration might be interesting when it comes to migrating, optimizing, or resizing. You can use many software utilities on the market for your P2V, V2V, and disk resizing operations, but the use of the VMware Converter standalone tool is advised and in most cases is trouble-free.

Another part of P2V or V2V work can be a situation when you want to resize a virtual disk or reclaim some dead space from within a thin provisioned disk. This can be done with the VMware converter. To resize the destination virtual machine's (VM) disk and optimize its layout.

The product has evolved over recent years, and VMware still actively maintains this product, but there are some good practices for using it and to maximize the benefits. In this post, we'll talk about all of them.

Here is a short list of tips that might be useful:

Uninstall all unnecessary software – Before P2V, uninstall any software you won't use on the system once it's a VM. This could be any diagnostics, monitoring software related to the physical server, or other software.

Disable services – There might be services that you want to disable, such as services related to disk activities, as those services will slow down the conversion process.

Chose only disks you want to convert and the right size – During the wizard that you launch before the conversion process, you have the possibility to select the disks you want to convert and then also

Create optimized partition layout

Create optimized partition layout

Downgrade virtual machine version – This is possible via the vCenter Converter, within the workflow. You might be in a situation where you have received a VM from your software developer or an external company and this VM was saved in a newer format than your current VMware vSphere environment, so the VM cannot run.

You must downgrade the VM hardware first. You can do this through the V2V reconfiguration process.

Downgrade virtual machine version

Downgrade virtual machine version

Option to "Connect to another server" – This option allows you to connect to another converter server remotely and manage the jobs that this "node" is doing. Imagine you have a lot of conversion tasks to do. Instead of using only a single node, a single machine for all conversion tasks, you can run many conversion tasks in parallel.

You can create a bunch of converter server nodes and launch multiple conversion tasks at the same time.

Connect to another server

Connect to another server

Disable anti-virus software – You should stop AV services, or completely disable the AV software. Some AV software might not allow you to do so. In this case, it's better to uninstall and then reinstall it once you have the VM up and running after the conversion.

Save your IP configuration – Before the conversion starts, you might want to save your IP configuration. If you're converting a server with a static IP, reconfigure it for DHCP, if you can.

You can do "ipconfig /all >c:\ip.txt" to save your IP configuration into a text file on your C drive.

After-conversion tasks – Yes, there are some tasks to do after the conversion as well. You can do without, but to get the best possible performance, you might want to check that as well.

  • If you're converting a really old OS (such as Windows NT4e), you should start the VM in safe mode first.
  • If you haven't done so before the conversion, you should uninstall RAID management tools, network teaming or management software, wireless card management software, and video and sound drivers. Restart in the normal mode. Do not restart if prompted by an uninstall program, unless you have finished with all the uninstallations.
  • Remove all unnecessary virtual hardware.

Remove "ghosted devices" – These are devices that are invisible in the device manager (Windows VMs only) but were brought in with the conversion process. It might be some RAID cards or hardware that is not needed/used in a VM.

On your VM, go to Start > RUN > CMD > Enter, and then type this command:

Open a device manager and go to View > Show hidden devices.

Show hidden devices

Show hidden devices

Use VMXNET 3 network cards – After the P2V, make sure that your VM is configured with VMXNET 3 NICs for the best performance, and not with E1000. These are the latest NICs, also called paravirtualized NICs, which are the most performant and most advanced virtual NICs. This type of NIC does provide multi-queue support (Receive Side Scaling in Windows), IPv6 offloads, and MSI/MSI-X interrupt delivery.

Use VMXNET3 network adapters

Use VMXNET3 network adapters

If there are migration problems, use local installation – If your conversion fails for no reason, install the converter software directly on the source system. You might experience migration issues or network latency between the converter server and converter worker. In this situation, it might help. Install the converter locally and "push" the bits into your virtual infrastructure or ESXi host.

VMware vCenter Converter has a long history, which is good for troubleshooting in case you have problems. There are many issues that are already documented in forums and VMware KB articles. Make sure to check them out.

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  1. @Vladan: Thank you for your interesting article. About the paragraph "If there are migration problems, use local installation". Yes I confirm that is the perfect solution, I wasted time some time ago exactly about this issue, a P2V conversion failed without any additional info or known reason. The only solution was install and run the converter on the local server.


  2. Sean 12 months ago

    If the source physical machine has a single hard disk with multiple partitions (C:, D:, etc.), I recommend using the "Designation layout" tab to assign each partition to its own virtual disk. This will give you greater flexibility with disk size adjustments and datastore layout in the future.


  3. Uttam Kumar 10 months ago

    Hi ,

    we have tons of VMs running under 5.5 U3. now we are planning to migrate /or move to 6.5 U3, do you feel the V2V is the best approach where DVS switch configured in 5.5 environments, thnx for ur time.




    • Author

      Your VMs with hardware compatibility for 5.5 will run just fine in 6.5 environments.

      As for DVS switch, this has no impact on VMs. 

      Unless you're doing "in-place" migration, but I doubt that hardware is compatible.


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