Hi @odrive9,
Thanks for the additional information. I think I understand. It sounds like you basically want to use odrive to create a local caching layer on your NVMe for your external drive. This is an interesting use case.
odrive expects some sort of “storage service” to sync to, so you could do this by using something like SFTP, FTP, WebDAV, or even the basic MinIO server (https://docs.min.io/docs/minio-quickstart-guide.html) to facilitate the client/server relationship that is needed.
Basically, setup up a simple server on your system that is pointing to your external drive and then link that to odrive. This external hard drive will then show up in your odrive folder as another link and be syncable.
This reminded me of a post from a while ago where another user was looking to sync two external drives to each other. Your use case is actually simpler than that, but along the same lines: Can I sync two local locations directly with odrive?
Let me know if you have any questions on the above.