The Personal vDisk feature in XenDesktop retains the single image management of pooled and streamed desktops while allowing people to install applications and change their desktop settings.
Unlike traditional Virtual Desktop Infrastructure (VDI) deployments involving pooled desktops, where users lose their customizations and personal applications when the administrator alters the base virtual machine (VM), deployments using Personal vDisks retain those changes. This means administrators can easily and centrally manage their base VMs while providing users with a customized and personalized desktop experience.
Personal vDisks provide this separation by redirecting all changes made on the user's VM to a separate disk (the Personal vDisk) attached to the user's VM. The content of the Personal vDisk is blended at runtime with the content from the base VM to provide a unified experience. In this way, users can still access applications provisioned by their administrator in the base VM.
Personal vDisks have two parts, which are by default equally sized:
Personal vDisks support the provisioning of department-level applications, as well as applications downloaded and installed by users, including those that require drivers, databases, and PC management software. If a user's change conflicts with an administrator's change, a Personal vDisk provides a simple and automatic way to reconcile the changes.
In addition, locally administered applications (such as those provisioned and managed by local IT departments) can also be provisioned into the user's environment. The user experiences no difference in usability; Personal vDisks ensure all changes made and all applications installed are stored on the vDisk. Where an application on a Personal vDisk exactly matches one on a master image, the copy on the Personal vDisk is discarded to save space without the user losing access to the application.
An algorithm automatically adjusts the relative sizes of the two parts of the vDisk depending on how the vDisk is used. For example, if a user installs several big applications on the Personal vDisk so space becomes limited, the application space is increased relative to the space for user data. The overall size of the Personal vDisk does not change. You can configure this resizing feature.
Physically, you store Personal vDisks on the hypervisor but they do not have to be in the same location as other disks attached to the virtual desktop. This can make Personal vDisk storage cheaper.