How do I back up a whole partition?

I would like to backup my whole partition /dev/mmcblk0p2 as kind of an ad-hoc generated image file, because it’s file system is btrfs and backing up contained files themselves would not keep the internal structure (think of snapshots).

I tried to generate a symlink via ln -s /dev/mmcblk0p2 /my/backup/repository, but duplicacy doesn’t want to follow that symlink, even though it is in the root of the backed up repository. Probably because it doesn’t lead to a directory.

Is there another way to do this? Note that the repository also contains other content, that lies next to the mentioned symlink.

Right Duplicacy only follows a symlink in the root only if it points to a directory. I don’t know if there is a creative way to back up an entire partition, but if we change the behavior to follow first-level symlinks that are files maybe that is the right solution.