Is there an external solution (on file system) to upload PDF files rather than copy them in the JCR repositories?
The creation of a VFS mount point is the adequate solution:
Administration > System components > Mount points.
Beforehand, a folder has to be created in one of the file systems that Jahia can access (D:/pdf-files for instance).
The VFS mount point is created as below:
You have to check that you can access this folder in the Repository Explorer :
Managers > Repository Explorer > root > mounts > pdf-files : you should see the list of your PDF files.
Finally, you check you can access and upload these PDF files from the Document Manager :
Managers > Document Manager > External Repositories > mounts > pdf-files : you should see the list of the PDF files and with a right-click on "pdf-files", you can upload new files.