Add a backing device to an existing bcache device

Question

I currently have a bcache device with one SSD as cache and one HDD as a backing device.

Is it possible to add another backing device without loosing the files already on the bcache device?

Answer 1

Once everything is writen out of your bcache device to the HDD it caches for, you should be able to swap things around without issue.

• The bcache device is just there to store data untill it can be writen to disk. It is a way of getting more performance from slower HDD's. On systems with large file transfers occuring regularly, this is a great thing.

For more information look here: https://www.spinics.net/lists/linux-bcache/msg03359.html