Guest OS ID Purpose

[kitch]

I understand that this field is used for VMware Tools installation. And some specific OS related H/W packages, but if this field is set to a 32-bit OS when it's actually a 64-bit OS, are there any performance hits associated with this mis-configuration? Is the VM only using the the 32-bit architecture on the vCPU?

[a_p_]

The guest OS setting is used when creating the VM to configure the appropriate virtual hardware which fits best for the guest OS and it is also used for default configuration settings and optimizations to ensure the guest works properly.

André

[Troy_Clavell]

I'm not quite sure I follow you... Are you referring to the Guest Operating System field underneath tthe Options tab of the settings of the guest? This is helpful in allowing vCenter and ESX know what tools need to be mounted during the install process.  Plus, if these are inaccurate reporting will be off as well.  However, the day to day functions of the underlying guest , it's OS and applications will not be impacted by this field being mislabeled.

The only way to change it is to power down the guest.

[kitch]

Yes, I was wondering if it made a difference to the underlying OS esp. when the architecture was wrong.

Thanks,

Kevin

[continuum]

.. if this field is set to a 32-bit OS when it's actually a 64-bit OS, are there any performance hits associated with this mis-configuration?

thats undocumented.
guestOS = x sets an unknown number of vmx-file parameters that are not printed to the vmx-file.

The effects of this may vary depending on your host CPU, effective guest OS flavour , and what not ....
Setting this wrong may result in effects like Windows 2003 detects the wrong type of E1000 nic, a Linux guest may get an unusable mouse, an ESXi guest may not be able to run nested VMs .... just to name a few.

Most of the times it is best to get the closest match: for NetBSD guest use FreeBSD, for Windows 9 guest use Windows8 and so on.

If you are lucky jmattson will give you a good final answer

[admin]

kitch wrote:

I understand that this field is used for VMware Tools installation. And some specific OS related H/W packages, but if this field is set to a 32-bit OS when it's actually a 64-bit OS, are there any performance hits associated with this mis-configuration? Is the VM only using the the 32-bit architecture on the vCPU?

There are not likely to be any performance hits.  You may run into other issues, such as virtual devices (e.g. buslogic SCSI) that can be configured for a 32-bit VM, but which are unsupported for a 64-bit OS.