Part of the final phase of a Horizon upgrade includes upgrading View Composer desktop pools.

Upgrading pools that were created with View Composer requires that you use a snapshot taken after upgrading Horizon Agent on the parent virtual machine.

Important: If you use View Composer linked clones and you want to use the space reclamation feature available with vSphere 5.1 and later virtual machines, you must configure certain settings in View LDAP and in Horizon Administrator, in addition to performing the steps in this procedure. For a complete list of tasks, see Tasks for Upgrading Desktop Pools to Use Space Reclamation.
Note: If you are also upgrading the virtual hardware version, such as upgrading to virtual hardware version 8 or later, included with vSphere 5 or later, the snapshot of the upgraded parent virtual machine is used to upgrade the virtual hardware version of the rest of the virtual machines in the linked-clone pool.

Upgrading in this way, from one virtual hardware version (or compatibility level) to a higher version, is supported. You cannot, however, recompose linked clones to a lower hardware version than their current version. For example, you cannot recompose hardware version 8 clones to a parent virtual machine that is hardware version 7.



  1. If you disabled provisioning of new virtual machines in preparation for the upgrade, enable provisioning again.
  2. To turn on the 3D rendering feature, edit the pool to configure the following settings:
    • Set the pool to use the PCoIP display protocol or the VMware Blast display protocol.
    • Set Allow users to choose protocol to No.
    • Turn on the 3D Rendering feature.
  3. To enable the space reclamation feature available with vSphere 5.1 virtual machines, in the Advanced Storage section of pool settings, select Reclaim VM disk space, and set the threshold for space reclamation to 1GB.
  4. To enable View Storage Accelerator, available with vSphere 5.0 or later virtual machines, in the Advanced Storage section of pool settings, verify that the Use View Storage Accelerator check box is selected.
    View Storage Accelerator can improve performance during boot storms and anti-virus scanning I/O storms by allowing ESXi hosts to cache common virtual machine disk data.
    Important: This feature is turned on by default. View Storage Accelerator requires 1GB of RAM per ESXi host.
  5. Use the snapshot you created after upgrading the parent virtual machine to recompose desktop pools.
  6. If you changed the Refresh OS disk on logoff setting for a pool to Never in preparation for the upgrade, change the setting back to reflect the appropriate refresh policy.
  7. If you canceled any refresh or recompose operations for any desktop pools, schedule the tasks again.

What to do next

Upgrade the clients. See Upgrade the Client Application.

Perform the tasks listed in Post-Upgrade Tasks to Enable New Features in Your Horizon Setup that apply to your setup.