Linux Servers for Infrastructure

[Null Ack]

Im reflecting on a infrastructure project I did recently and how this
might have been done using Linux servers (Ubuntu). In this example the
desktops have to remain the approved XP SOE. To give an outline of the
environment:

* 1450 desktops running Windows XP on a SOE in three buildings
separated via fibre connections
* Beyond the SOE applications are packaged into MSI's and controlled
via group policy
* AD is used throughout

The services for the servers are:

* File serving over the fibre connection to the large replicated SANs
(there is two) that stores all data
* Authentication
* Software distribution for patches and MSI packages to be installed
into the desktops as allowed by group policy
* DNS
* Mail
* NTP
* Intranet and Internet web serving
* Print serving
* Monitoring and alert system
* Single sign on
* Security auditing of desktops

Two eight way servers (for scalability) were depoyed in seperate
physical locations and setup in a cluster for all services to allow
for online maintenance of one node. The servers had no internal
storage and they booted off a LUN in the SAN.

Im not sure about the software distribution aspetcs and group policy?

Im curious about this. What I see happening is Linux being used for
app / web / DB servers but not alot in infrastructure for desktops -
maybe it just the places Ive worked at.

Thoughts?