title_body: How to manage my e-book library across my devices
upvoted_answer: Ok, so here is my current solution, which is not perfect but that corresponds more or less with my current need.
  
  
  PC with windows are using the portable version of Calibre. The library and the metadata are stored in a specific dir in  my filesystem that is synchronized with my local onedrive directory.
  Android devices are using the Calibre Companion app ($4) and are configured to use my onedrive cloud account.
  I'll probably change that in order to use a cloud synchroniser tool to mirror my cloud storage to the SDCard and point Calibre Companion to my local storage instead !
  IOs: don't need it at the moment.
  
  
  What needs to be improved:
  
  
  possible conflict between metadata of pc version: I need to investigate if I can have a centralized version of calibre that can received updates from secondary devices. But right now I use the same machine for adding new stuff, so is is fine.
  Need to find a way to push my ebooks with DRM to calibre. No really needed, because Kindle app is ubiquitous, but I would like to have one central place to organize my ebooks collection.