An OverlayFS mount can have its ‘lowerdir’ (read-only image layer(s)) and ‘upperdir’ (read/write container layer) on different file systems.
It makes sense to me to use this functionality in Docker, as in this way image layers could be stored on an SSD (fast access, no writes) whereas the container layers could be stored on a HDD (no space issues, more durable in terms of write-cycles). Our docker containers can grow large due to large temporary files (medical image analysis), which means that storing everything on an SSD is a no-go.
Is it currently possible to configure Docker this way? How? And if not, is it a feature worth implementing in a future release?