VDI is often categorized as either Non-Persistent or Persistent.
Non-persistent VDI is where you use a shared common image. Only one image to maintain. When the user logs off, the image is destroyed and the next time the user logs on they get the original image.
Persistent VDi is where the complete image is retained upon logout and the next time the user logs on they get the exact same image they had when they logged off.
The reality is that usually Non-persistent VDI implementation brings along some user data from the prior session. This is handled by Roaming Profiles at a minimum, but may also have folder redirection or a user environment add-on product to manage the user-related-data, either app related (UEV, AppSense, RES, TriCerat, Norskale, etc) or layering (Unidesk, Citrix PVD, 2012R2 “User Layer”).
I think we need a different term for this, segregating it from Non-persistent. I’m going to start calling this “Semi-Persistent”. What do you think?