First published on CloudBlogs on Jan, 04 2010
The two virtual machine deployment scenarios supported by the Microsoft VDI solution are: 1) Virtual desktop pool and 2) Personal virtual desktops. These two scenarios present two different models of assigning virtual machines to end users. This post explains the virtual desktop pool scenario.
A virtual desktop pool temporarily assigns a virtual machine to the user. The Remote Desktop Connection Broker (RD Connection Broker) automatically makes this assignment without any prior assignment configuration. The user–to-virtual-machine assignment is removed as soon as the user logs off. Since there is no permanent assignment of a virtual machine in a virtual desktop pool to a user, as long as there is a virtual machine available in the pool, one will be assigned to the user. It is a misconfiguration to assign a virtual machine in a virtual desktop pool to a user as if it were a personal virtual desktop. When a user makes a connection to such a personal desktop which is part of a virtual desktop pool, the connection will fail and a target mismatch event is logged by RD Connection Broker.
A virtual desktop pool is a group of identically configured virtual machines on a Remote Desktop Virtualization Host (RD Virtualization Host) server. Users can access the virtual machines in a pool through RemoteApp and Desktop Connection or RD Web Access. When a user clicks on the Virtual Desktop pool icon, RD Virtualization Host prepares a pre-created virtual machine from this virtual desktop pool for a remote RDP connection. A virtual machine can be a member of only one virtual desktop pool. All virtual machines in a virtual desktop pool are identically configured; a user sees the same virtual desktop regardless of which virtual machine in the virtual desktop pool the user connects to. Since a user might be connected to a different virtual machine in the virtual desktop pool each time he logs on, it is recommended to use roaming profiles and folder redirection to centrally manage user settings and data. Please refer to the link for more details:
To assign a virtual machine from a virtual desktop pool a Hyper-V server which has the least number of running virtual machines is chosen and a virtual machine belonging to this virtual desktop pool is selected. A random selection is made if two or more Hyper-V servers have the same number of running virtual machines. ISVs can enhance the inbox solution by implementing their own load balancing algorithm. Please refer to the link for more details:
When a user disconnects from a virtual machine in a virtual desktop pool, the user will be redirected to his disconnected VMs the next time he logs back. However, when a user logs off from the virtual machine, the virtual machine can be configured to rollback (refer to the links at the end on how to set up a virtual desktop pool to find details on this) to a state determined by an administrator. Since a user might be connected to a different virtual machine in the virtual desktop pool each time he logs on, it is recommended to use roaming profiles and folder redirection to save user state.
A virtual desktop pool can span multiple Hyper-V servers with each server possibly having virtual machines from multiple virtual desktop pools. The 3 supported guest operating systems inside a virtual machine are –Win7, Vista SP1 and SP2 and XP SP2 and SP3. For details on the specific versions of these software please refer to the following link -
For details on how to set up a virtual desktop pool, please refer to: