XenDesktop pools verse dedicated machines

Choosing pooled verses dedicate machines depends mainly on the access and control you want to grant the user of the virtual desktop.

Pooled – good for task workers

1. Pooled machines provide desktops that are allocated to users on a per-session, first-come first-served basis. For pooled-static machines, users are assigned a specific machine from the pool when they first log on to XenDesktop. Users are connected to the same machines for all subsequent sessions. This allows users of pooled-static machines to be associated with specific VMs, which is a licensing requirement for some applications.
2. Pooled-random machines are arbitrarily assigned to users at each logon and returned to the pool when they log off. Machines returned to the pool are available for other users to connect to.

Pooled desktops are freshly created from the master VM when users log on via the provisioning server.

Any changes that users make to their desktops are stored for the duration of the session, but are discarded when users log off. Of course you can use profile manager to help with this and store the user details.

This solution maintains a manually created single master VM in the data centre dramatically reduces the time and effort required to update and upgrade users' desktops. This allows you to periodically replace this master for patches etc.

Dedicated – good for power users and administrators

1. Dedicated machines provide desktops that are assigned to individual users. Machines can be assigned manually or automatically assigned to the first user to connect to them. Whenever users request a desktop, they are always connected to the same machine, so you can allow users to personalise their desktops to suit their needs.

Dedicated desktops are pre-created from the master VM via the snap-shot and the first time that users log on, they are assigned this machine. Several users can access the same machine (at different times).

Maintains an automatically created snap-shot of the catalogue master VM. But as for changes, the user has to look after the computer or you re-mint them a new image as needed.

Sources: http://support.citrix.com/proddocs/topic/xendesktop-rho/cds-choose-scheme-type-rho.html