Continuing the discussion from How long does the Gliffy mass import to draw.io take?:
Better late than never: For further looks at this question. No shut down of confluence is neccessary for the mass import to work. It´s quite easy steps. Have a look at this documentation to get all information you need about the mass import.
The estimated time for a complete import depends on the amount of diagrams you have. Additionally we recommend everyone to do some tests of the import on several confluence spaces before converting all diagrams at once.
Hope that helps!
Samuel
Fore more general info on draw.io for Confluence or Jira, please refer to our draw.io webpage.
And some great blogposts! Blog - draw.io