If you think VDI is complicated, you are welcome to the subject of storage. There is a lot to consider; so, read the chapter and put some thought into it. You need storage for the virtual desktops in addition to the XenDesktop servers themselves.
Storage is an important component of virtualization. You need storage, and lots of it, to store the virtual machines and user data. The only exception to this is if you are using the Provisioning Server (PVS) or XenServer with thin provisioning. The amount of storage available is determined by the type of architecture you implement, dedicated desktops versus shared desktops. As you can imagine, having dedicated desktops for each user will really start to eat up disk space. Shared desktops use a shared VDI image with the ability to store user data in a Personal vDisk (PvD) partition, which requires considerably less storage and keeps the costs down. Storage can be locally attached to the Hypervisor...