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ac427
Enthusiast
Enthusiast

Downgrading virtual hardware version 8 to version 7

The method below shows how to convert from virtual hardware v7 to v4 without using VMware Convertor.

Would there be any changes to this method, to convert a v8 vm to a v7 vm?

Is it really necessary to remove all snapshots before using this method?

If not, this method would preserve the snapshots, that would normally be lost using VMware Convertor.

The source vm is using the scsi0.virtualDev = “lsisas1068” scsi controller.

Because this is available in ESXi 4 with virtual hardware v7, would i be right in thinking i only have to change:

virtualHW.version = “8” to virtualHW.version = “7” in the vmx file?

  • Make sure you have a good backup of the VM
  • Power off the VM
  • Make sure the VM doesn’t have any snapshots before proceeding
  • From the ESX console or from a Putty session, edit the VMs VMX file, using your favorite editor
    vi /vmfs/volume/DS1/WIN2008-001/WIN2008-001.vmx

  • Change the virtual hardware version from:
    virtualHW.version = “7”

    to

    virtualHW.version = “4”

  • You don’t need to change config.version = “8”, since ESX 3.x already uses this version
  • Change the virtual controller, because virtual hardware version 4 doesn’t understand the version 7 virtual controller, from:
    scsi0.virtualDev = “lsisas1068”

    to

    scsi0.virtualDev = “lsilogic”

  • From the ESX console or from a Putty session, edit the VMs VMDK pointer file/files (if more than one virtual disk), using your favorite editor
    vi /vmfs/volume/DS1/WIN2008-001/WIN2008-001.vmdk

  • Change the virtual hardware version from:
    ddb.virtualHWVersion = "7"

    to

    ddb.virtualHWVersion = "4"

  • You should now be able to power on the VM as virtual hardware version 4.

Found at http://www.amikkelsen.com/?p=557&cpage=1#comment-8639

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6 Replies
PduPreez
VMware Employee
VMware Employee

Hi

I do not believe these steps would work.

This was specific to the changes between version 4 and 7

At the moment it seems there is no method to downgrade virtual hardware to 7 other than reverting to snapshot or using converter

From http://KB Virtual Hardware versions

When you upgrade from virtual hardware version 4 to version 8, the upgrade is reversible if you take a virtual machine backup or snapshot before performing the upgrade.

Please award points for helpful/correct answers Smiley Wink

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ac427
Enthusiast
Enthusiast

I thought it would work unless you were using unique virtual hardware version 8 features like 1TB or ram or 32vCpu's.

The method does cover v7 to v4 but the principle should surely be the same?

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Cannoli
Contributor
Contributor

This appears to work based on some initial testing I just performed.

I created a version 7 XPx86 VM in ESXi 5

Cloned it on a shared datastore

Upgraded the original version 7 VM to version 8

Powered it off and removed if from the inventory

I edited the .vmx file and changed the virtualHW.version to "7"

I imported this modified version 8 VM into ESXi 4

Pressed play and logged into the XP OS without problems (that I can see)

I actually changed everything that said version "8" to version "7" in the .vmx file.  I need to try it with just the two changes listed in the first post of this thread.

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GBCFS
Contributor
Contributor

Sounds incrediable if this works.

At the moment having to run a conversion from vSphere 5 to vSphere 4 cluster and converting at about 180k/s. A client VM of about 15GB takes over a day. At that rate, converting a server VM would take 1-2 weeks.

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GBCFS
Contributor
Contributor

Thanks for sharing this info. After upgrading all our VMs to HW version 8 on vSphere 5, had need to downgrade some for testing.

This method has saved me hours and worked perfectly, just changing all the instance where HW version 8 was referred to (about 5 times).

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rgpowell
Contributor
Contributor

Hi

Looking to down grade the virtual Hardware on a Linux server, do you think this process will work??

Also looking at going from version 8 to 4??

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