Updating User Writable Volumes

Updating User Writable Volumes

Why Update User Writable Volumes?

While typically less common than upgrading AppStacks, there are cases where you will need to update files on writable volumes.

When user writable volumes are created, a number of predefined batch files are included by default. You might need to add or modify these batch files to meet the needs of end users. For more information about advanced App Volumes configuration and the available batch files, see Batch Script Files in the VMware App Volumes Administration Guide.

Updating a writable volume basically involves creating and uploading a ZIP file that contains files you want to add or change. You cannot change any user-installed applications that are already in the writable volumes. The files in the ZIP file you upload become available to the user after the user logs in twice or reboots the machine twice:

  • The first login or boot will copy the files to the writable volume.
  • The second login or boot will apply the files for use.

Prerequisites for Writable Volumes Updates

Before you begin the process of updating your end users' writable volumes, you might need to find out what is in the writable volume. It is possible to view the content of AppStacks or writable volumes with simple desktop tools. You can use 7-Zip or Far Manager to open an AppStack or a writable volume. You cannot edit them, but you can view content if needed.

If you plan to update a single writable volume you will also need a VM that does not have the App Volumes Agent installed.

Workflow to Update All User Writable Volumes

User writable volumes can be updated using the App Volumes Manager web interface. You might want to update a single file (such as snapvol.cfg), or multiple files, on the user writable volumes.

Important: The following process will update all user writable volumes. Updating individual volumes is covered in the Workflow to Update an Individual Writable Volume section of this tutorial.

1. Create a ZIP File

First, you will create a ZIP file containing all files to be updated or added. The ZIP file must be 5 MB or smaller.

1.1. Update Writable Volumes

  1. Log in to the App Volumes Manager console, and navigate to Volumes > Writables.
  2. Click Update.

1.2. Upload the ZIP File

  1. Click Upload.
  2. Click Choose File.
  3. Navigate to the ZIP file containing the file or files that need to be changed.

Once the upload is complete, App Volumes Manager will start to update the user writable volumes that are not currently in use by end users.

Important: Keep in mind that a writable volume can only be updated when it is detached.

2. Complete the Update Process

Notify end users to complete two user logins or two computer boot operations so that the new or updated files can be applied to the writable volume:

  • The first login or boot will copy the files to the writable volume.
  • The second login or boot will apply the files for use.

Workflow to Update an Individual Writable Volume

If you need to update only one writable volume or a specific writable volume, you will not be able to use the built-in update process in the App Volumes Manager web interface.

Instead, use the following alternate method to update the writable volume.

1. Select the Writable Volume

To determine the file name of the writable volume you want to update, use the App Volumes Manager console and look up the name of the writable volume’s VMDK file.

In this example, the file name is VMWDEMO!5C!testuser2.vmdk.

2. Mount the Writable Volume to a VM

  1. Make sure you have a VM that has no App Volumes Agent installed on it.
  2. Log in to the vSphere host where the VM resides.
    Note: Be sure to log in to the specific vSphere host rather than vCenter Server. Attempting to perform this step using the vCenter Server console will result in an error indicating the volume cannot be opened for writing. Using the web interface of a specific vSphere host is one way to avoid this issue.
  3. Edit the virtual hardware settings of the VM.
  4. Select Add hard disk and choose the Existing hard disk option.
  5. Power on the VM.

3. Log In to the Windows VM

  1. Navigate to the Windows Disk Management console.
  2. Verify that you can see a drive called CVWritable.

4. Change the Drive Letter for CVWritable

  1. Navigate to the lower-right part of the Disk Management console.
  2. Right-click the CVWritable disk and select Change Drive Letter and Path.
  3. Assign an available drive letter to the drive. E:\ is used in this example.

5. Change the Content on the User Writable Volume

  1. Use Windows Explorer to navigate to the CVWritable drive (E:\ in this example).
  2. Review the contents of the drive.
  3. Add, edit, or delete files or folders as needed for the individual writable volume.

6. Detach the Writable Volume

  1. Once you have completed the changes, log out of the VM and power it off.
  2. Go back to the vSphere host console, edit the virtual hardware of that VM and click the X to detach the VMDK.


You have now finished updating the writable volume and made it available to its assigned user again.

As you can see, modifying one writable volume is not as simple as updating all of them. We recommend using the built-in functionality when possible, but if for some reason there is an issue with a specific user, you now know that you can modify a single writable volume.