VCAP-DTD | Objective 2.1 | Create a Desktop Virtual Machine Design

Determine the appropriate virtual machine configuration(s) that will satisfy design requirements

The first part of Objective 1.1 talks about Functional and Non-Functional Requirements. These requirements are likely to start to form some of the design requirements for VM configuration. Typical requirements for View deployments tend to include:

  • The desktops must run Windows 7 x86
  • All desktops must have Microsoft Office 2013 installed (To include Outlook, Word, Excel, One Note).
  • Desktops must be protected with the corporate Anti Virus solution
  • Developer desktops must have the ability to work with 3D graphics
  • User profiles must be redirected to corporate NAS solution.
Map your use cases to virtual machine requirements.
The virtual machine hardware configuration will vary depending on the compute resources that are required for that use case.
Create a separate virtual machine for each memory and disk size combination.
Guidelines from VMware (remember this is an exam not real life!) state:
  • Configure on 1 vCPU
  • Configure only 1 vNIC and use the VMXNET 3 adapter
  • Use the LSI Logic SAS or Parallel adapter
  • Remove the floppy and CD/DVD drives
  • Disabel virtual machine logging

Remember that VMware View adjusts the video RAM according to the number of monitors and the maximum screen resolution configured in your pool settings and managed by View Composer.

When assigning the amount of vCPUs take into account the following:

  • A physical machine competes only with itself
  • A virtual machine shares its resources and competes with other virtual machines. Assigning more CPU or memory than is necessary does the following:
    • Impacts all users
    • Limits virtual machine density
  • Assigning multiple vCPUs impacts CPU scheduling. See a brilliant video by Ray Heffer here explaining why this shouldn’t be done
    • Also using multiple vCPUs will dramatically decrease virtual machine density per host
  • VMware recommends assigning one vCPU unless there are specific and substantiated requirements for more
    • Windows 7 desktops that need to play 720p HD video and are using PCoIP will require 2vCPUs
  • If certain use cases require multiple vCPUs then assign them in their own pool
When calculating the amount of memory to assign to your desktop, take into account the following:
  • Too much memory will inflate both the VM swap file and the Windows page file
  • Too little memory will dramatically impact the user experience
  • Windows paging file size and activity affects linked clones
    • If the page file is on the OS disk, then OS disk will grow
    • If the page file is on a disposable disk, its size also grows as it’s thin provisioned
  • Ensure you use assessment data to determine optimal memory assignments
  • VMware recommends minimising the page file size and, if linked clones are deployed, using a disposable disk for the page file and temp folder
  • VMware also recommend not selecting ‘Suspend’ to “Remote Desktop Power Policy’ in the pool settings

Establish image design requirements

These requirements will again tend to come from the functional and non functional requirements with assistance from your assessment software. Generally some of this information will come out of interviews.

We need to:

  • Identify the number of use cases
  • Identify any security and compliance requirements
  • Determine where user profile data will be stored
  • Determine where the page file and temp folders will be stored (Disposable Disks)
  • Determine what optimisations will be acceptable on the design to enhance performance
  • Determine printing requirements? (ThinPrint)

Establish OS requirements

  • What version of Windows will we be using?
    • Windows 8
    • Windows 7
    • Windows XP
  • Will it be x86 or x64
  • Which edition of Windows will be used?
    • Professional
    • Enterprise
  • Ensure we have KMS licensing available (View Composer does not support MAK when using linked clones)

Based on customer requirements, determine the number of images for the design

The information we need here would normally be available to use by the time we have gone through all the previous workings.

Utilise the data received from your assessment software along with the output from your interviews with stakeholders.

Complete your use case mapping to assist with mapping the users to number of images.

Try and ensure:

  • You have the least number of parent images/templates possible to ensure ease of management
  • Security and compliance is adhered to.

Identify applications to be virtualised or natively installed

With View (any virtual desktop) deployments the aim of the game is to minimise the bas system image.

As we are well aware, applications can be installed as part of the base operating system template, however:

  • Only do this for applications that will be used by everyone in that use case
  • Try an leave these to dedicated desktops only

Try and install applications using software distribution technology such as SMS.

Utilise ThinApp where possible to virtualise applications. Analyse both the user groups and the application profiles that have already been developed as part of the design process. From this, you should be able to determine the degree to which each of these templates will be able to make use of ThinApp. You may be able to reduce the overall number of templates/master images required by removing these applications from the master build and virtualising them with ThinApp.

Establish peripheral device requirements

Identifying peripheral requirements will again need to map to use cases and will determine the number of images and pools that will be created in the overall solution. Through environment analysis and stakeholder interviews we should have already identified what peripherals are in use and what requirements they may have. Remember that USB redirection is provided with the View client running on Windows 7, Windows XP and Windows XP Embedded.

If thin clients are going to be used then they will require some kind of USB redirection component.

Make use of GPO to restrict some USB devices where not appropriate for example, call centre agents taking credit card details etc.

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