Andy Baker wrote a good post on the Citrix blogs about the Hardware and Storage calculator.
During your desktop transformation project, you’ll need to estimate hardware and storage requirements so that project costs can be calculated and the infrastructure can be ordered. To provide an accurate estimate you’ll need to consider many different factors – including virtual desktops per host, virtual desktops per site, desktops per controller, users per XenApp Server, XenApp Servers per host, users per farm, hosts per resource pool, IOPS per VM and many others.
It’s a lot to consider – so where’s a good place to start?