"IIS application pool" is a Plesk feature, which serves websites and web applications hosted on a server.
Dedicated IIS application pool allows you to have a level of isolation between websites. Since each dedicated application pool runs independently, errors in one application pool belonging to one user will not affect the applications running in other application pools dedicated to other users.
By default, a Plesk server offers a shared application pool for all users.
A dedicated IIS application pool is a feature provided with our plans as follows:
Basic Windows
All the users share the same common IIS application pool
Professional Windows
Each site has his own, dedicated IIS application pool
Fracto1 Windows and Fracto2 Windows
Each Fracto plan has his own dedicated IIS application pool, whih is shared amongst all the sites hosted inside the Fracto plan
Fracto Cloud Windows
The user can assign a dedicated IIS application pool to certain sites or plans, and leave the others to share a common IIS application pool.