PVS target devices booting using the XenServer emulated network adaptor.

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Article ID: CTX695456

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Description

An existing XenServer VM was reinstalled to create a PVS master target device VM.
Windows showed the network adaptor in use as “XenServer PV Network Device”.

A PVS vdisk was created from this master target device VM, and streamed to new production target devices.
These new production target devices appeared to have identical hardware when viewed in XenServer XenCenter.
However when booting from the PVS Vdisk they showed they were using XenServer emulated network adaptor “Intel® PRO/1000 MT Network Connection”.

If the master VM first had ghost NICs removed before creating the vdisk, production target devices would  BSOD during boot time.

The master target VM and product target VMs were then compared using XenServer console command “xe vm-param-get param-name=platform uuid=<vm_uuid>”
This showed the master target device had a different device_id and was missing other parameters.
The output of the command “xe vm-param-get param-name=platform uuid=<vm_uuid>” should be identical between the VM it was created on the VMs where the vdisk will be booted.

Cause

XenServer VMs which were created on older versions may have different virtual hardware configurations, and have different or less XenServer VM params, and different capabilities.

The old master VM in this case when compared with newly created product target devices was missing XenServer VM params and was using an old device_id param (platform:device_id=0001).
When windows from this old master VM was booted on newly created production target device VMs, it expects the older virtual hardware configuration and parameters and fails over to using the emulated network adaptor.

The output of the command “xe vm-param-get param-name=platform uuid=<vm_uuid>” should be identical between the VM it was created on the VMs where the vdisk will be booted.

Resolution

A new VM was created on XenServer to use as the master target device.

  1. Using the old master VM, PVS target device software was uninstalled and XenServer VM tools were uninstalled.
  2. The old master VM was shut down, and the hard disk was detached, it was then attached to the new master VM.
  3. The hardware configuration of the new master VM was confirmed using XenServer console command “xe vm-param-get param-name=platform uuid=<vm_uuid>”
  4. Using the new master, XenServer VM tools were reinstalled with required reboots and then the active network adaptor was confirmed as “Xenserver PV Network Device”.
  5. Using the new master, PVS target device software was reinstalled, and a new vdisk captured.
  6. This vdisk was then streamed to production target devices which were then confirmed to be correctly using the network adaptor “XenServer PV Network Device”.

Issue/Introduction

PVS target devices on XenServer were booting with the XenServer emulated network adaptor Intel® PRO/1000 MT Network Connection.
The XenServer emulated network adaptor Intel® PRO/1000 MT Network Connection should not be used on PVS target devices.
The emulated network adaptor has lesser performance than the paravirtualized adaptor.
Xenserver PVS targets should utilize the “Xenserver PV Network Device”.

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