Composer creates more than one data disk to store the components of a linked-clone virtual machine.

OS Disk

Composer creates an OS disk for each linked clone. This disk stores the system data that the clone needs to remain linked to the base image and to function as a unique virtual machine.

QuickPrep Configuration-Data Disk

Composer creates a second disk with the OS disk. The second disk stores QuickPrep configuration data and other OS-related data that must be preserved during refresh and recompose operations. This disk is small, typically about 20MB. This disk is created whether you use QuickPrep or Sysprep to customize the virtual machine.

If you configure separate Composer persistent disks to store user profiles, three disks are associated with each linked clone: the OS disk, the second virtual machine disk, and the Composer persistent disk.

The second virtual machine disk is stored on the same datastore as the OS disk. You cannot configure this disk.

Composer Persistent Disk

In a dedicated-assignment pool, you can configure separate Composer persistent disks to store Windows user-profile data. This disk is optional.

Separate persistent disks let you preserve user data and settings. Composer refresh, recompose, and rebalance operations do not affect persistent disks. You can detach a persistent disk from a linked clone and attach it to another linked clone.

If you do not configure separate persistent disks, the Windows profile is stored in the OS disk. User data and settings are removed during refresh, recompose, and rebalance operations.

You can store persistent disks on the same datastore as the OS disk or on a different datastore.

Disposable-Data Disk

When you create a linked-clone pool, you can configure a separate, nonpersistent disk to store the guest OS's paging and temp files that are generated during user sessions. You must specify the disk size in megabytes.

This disk is optional.

When the linked clone is powered off, Horizon 7 replaces the disposable-data disk with a copy of the original disk that Composer created with the linked-clone pool. Linked clones can increase in size as users interact with their desktops. Using disposable-data disks can save storage space by slowing the growth of linked clones.

The disposable-data disk is stored on the same datastore as the OS disk.