For fast access metadata SHOULD be stored on the internal drive of the plex server for fast access, but video thumbnails can use up all the space on an internal drive (my server has only a 128GB SSD drive), particularly for very large libraries.
This feature request would be to add a setting to designate an external drive just for video thumbnails. When playing a particular show or movie, the thumbnails for that particular content could be copied to the internal drive for fast access.
With the existing design, one can use regedit to direct all metadata to an external drive, but it is not recommended and may suffer performance issues. This request would allow for scalability for very large libraries without having to give up the thumbnail feature (which is what I currently have to do).
Thanks.