Creating vDisks

In Citrix Provisioning, the vDisk is the operating system disk image that target devices boot from. Instead of each VM or endpoint having its own full local OS disk, PVS lets machines stream from a centrally managed disk image.

A vDisk is not just one file. At minimum, it is typically a VHDX base image plus a PVP properties file. If versioning is being used, it can also include AVHDX differencing disks, which track changes made through vDisk versions. Citrix’s current documentation describes this same file relationship for vDisks and vDisk versions.

Key concept

Think of the VHDX as the actual hard drive image.

Think of the PVP file as the Citrix Provisioning metadata/properties file that tells PVS how to use that disk.

Think of the AVHDX files as version/update layers that sit on top of the base image when vDisk versioning is used.

This matters because when you are troubleshooting PVS, you need to understand that the “vDisk” shown in the console is really tied to multiple files in the store, not just one object in the console.

Standard Image vs Private Image

This is one of the most important PVS concepts to master.

Standard Image mode

Standard Image mode is the classic production PVS model. Multiple target devices boot from the same shared vDisk. The vDisk is effectively read-only to those machines, and machine-specific changes are redirected to write cache. Citrix describes Standard Image mode as the option used when multiple devices access the same image with write-cache options.

In real-world terms, this is what lets you run 10, 50, 100, or more VDAs from one golden image.

Private Image mode

Private Image mode is normally used for one target device at a time. The disk is writable, so changes made to the OS persist directly to the vDisk. Citrix describes Private Image mode as single-device access with read/write behavior.

In real-world terms, Private Image mode is useful when you are building, preparing, repairing, or directly modifying a vDisk. It is not usually how you want to run a large pooled production VDI environment.

The practical admin takeaway

For a PVS environment, the usual lifecycle is:

Build or capture a clean image.

Place it into PVS as a vDisk.

Use Private Image mode or a maintenance version when making changes.

Use Standard Image mode when deploying it to multiple VDAs or target devices.

Assign that vDisk to target devices through the PVS console.

Boot the targets so they stream from the assigned vDisk.

Citrix also notes that once the base vDisk is created, it is deployed by assigning it to one or more target devices, and the device boots from the assigned vDisk.

What I would remember for the exam and for real work

A vDisk is the shared boot disk image used by target devices.

A vDisk commonly includes .vhdx, .pvp, and possibly .avhdx files.

Standard Image equals shared, read-only, multiple devices, write cache required.

Private Image equals single device, read/write, persistent changes.

In production PVS, Standard Image mode is usually the magic. That is what gives you centralized image management.

When updating a vDisk, versioning creates differencing disks so you can make changes without replacing the entire base image every time. Citrix explains that differencing disks capture changes while leaving the base disk unchanged.

Lab task for this note

For your PVS lab, I would do this:

Create or import a vDisk.

Find the actual store path on disk.

Identify the .vhdx and .pvp files.

Put the vDisk in Private Image mode and boot one target device.

Make a small change, such as adding a folder or installing a small utility.

Shut down the target.

Switch the vDisk back to Standard Image mode.

Boot multiple target devices from the same vDisk.

Confirm that they can share the same image.

Then create a new vDisk version and watch for the .avhdx file to appear in the store.

Source links to keep handy

Citrix vDisk creation:
https://docs.citrix.com/en-us/provisioning/current-release/configure/configure-vdisks/vdisk-create.html

Citrix managing vDisks:
https://docs.citrix.com/en-us/provisioning/current-release/manage/managing-vdisks.html

Citrix updating vDisks:
https://docs.citrix.com/en-us/provisioning/current-release/manage/managing-vdisks/vdisks-update.html

Citrix replicated vDisk storage:
https://docs.citrix.com/en-us/provisioning/current-release/manage/managing-vdisks/vdisks-replication.html