Handle OST Files With VMware App Volumes

/ December 5, 2017/ VMware App Volumes, VMware Horizon

More and more companies are considering to migrate their mail to office 365, with that fact, the default standard non-dedicated VDI environment isn’t ready for handling ost files without additional tools. In this blog I will describe the use of VMware App Volumes “writable disk” for offloading the ost file.

In smaller environments, Mostly IT admins specify an alternative default location for saving the OST file. Note that saving the ost file on a file server, it will increase Read and write iops and is also not supported.

With VMware App Volumes, It admins can easily assign users to create and use Writable disk. when a user logged in, the writable disk ( vmdk ) will be connected to the virtual desktop ( Svdriver ). With writable disk, a user is allowed to save applications, data and settings.

Upload Prepackaged Volumes

This step will create writable templates, if you already done this, you can skip this section

1 Select the storage where you already saved the apps_template
2 Select the host, which has access to the storage
3,4 provide the ESX Username and Password
5 Select Writable_templates/template_uia_only_workstation.vmdk or Writable_templates/template_uia_plus_profile_workstation.vmdk

In my case, I’m already using VMware UEM for handling the user profile, so the best option for me is the first one “template_uia_only”

Create Writable volume

follow the following steps to create a Writable Volume

In my case for testing purposes, I used a test account “testuser” which is a member of the group domain\writable volumes.

  1. The box must be ticked
  2. Select “Template_uia_only.vmdk”

Additional, there are three options;

  • prevent user login, if the writable is in use on another computer
    because I used writable in combination with Outlook Ost, I selected this option to avoid problems within the ost.
  • Limit the attachment of user writable to specific computers
    With this setting, you can specify that the writable only must connect if the desktop start with the name “Test”,  with this setting you can exclude persistent desktops
  • Delay writeable creation for group/ou members until they login
    With this option there is no need for pre-staging volumes, writable will be only created if a user logged in for the first time. In my test environment the creation of the writable takes almost 773ms #note that this option doesn’t work if you create a writable for a specific user. the user must be a member of a group#

When i logged in with the test account in Horizon and launch a desktop, I can see in the task console of Vcenter two tasks;

  • Copy File
    this task makes a copy of the default writable volume which has been created when creating the writable volume ( as above )
  • Reconfigure virtual machine
    With this task, the writable volume will be mounted on the target machine, in this case the “vm-002”

Configuring GPO for Outlook

In my test environment, I’m using office 2016. For configuring settings with GPO, there are Administrative Templates ,after copying the Admx files to your policy store \\domain\SYSVOL\domain\Policies\PolicyDefinitions you can see additional policy setting while creating or editing gpo’s.

Users with a writable volume can use the default directory “C:\SnapVolumesTemp\writable” for saving the Ost file, It is a persistent directory. All files placed in this folder are saved in the .vmdk

Microsoft Outlook 2016/Miscellaneous/PST Settings
Default location for OST files Enabled
Default location for OST files C:\SnapVolumesTemp\writable

Microsoft Outlook 2016/Account Settings/Exchange/Cached Exchange Mode
Cached Exchange Mode Sync Settings Enabled
Select Cached Exchange Mode sync settings for new profiles: “Three months”
Use Cached Exchange Mode for new and existing Outlook profiles; Enabled

After setting the policy’s, I did some testing with my “testuser” account. Because the writable volume was created in previous step, the existing writable volume has been attached to the desktop


After starting Outlook, you can see in the explorer that a ost file has been created in the folder “C:\SnapVolumesTemp\writable” you can also check some settings at your outlook profile

So that is all, thanks for reading and good luck with testing this solution!



1 Comment

  1. Pingback: VMware App Volumes version 2.14 | Leclmaas.nl

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