Cloud providers typically offer different geographical data centers. During setup you can point to any one of these. Then when you want to offer global access to WSI data, you can store the data in multiple zones.
The different instances of PMA.core in these zones can share a single database, yet the mounting points of the root directories can refer to different endpoints in different locales.
Any time an end-user requests a particular slide from a particular location, PMA.core automatically selects the storage location closest to the accessed node.
See also Instance settings.