I've been looking into using OverlayFS. I'd like to be able to combine a bunch of already formatted, already containing data, hard drives. All hard drives are formatted with ext4.
The goal is to make it so I can use all the storage as one giant location. I currently make use of MergerFS so all the files contained do not overlap anywhere. I would like to move away from MergerFS because I had some issues and OverlayFS seems to be supported in the upstream kernel itself.
But I'm not sure how to configure OverlayFS to do this, is it even possible? On first glance it seems like I can only have one writable location and the other locations are just there to provide the files they have.