The Yoke driver provides transparant mirroring between disk partitions and other block devices (such as loop and nbd). It differs from the kernel RAID0 facility in that it is a virtual device with no interface of its own. To start mirroring one device to another requires no prior setup, just "yadd /dev/yd0 yet_another_device" and go. The yet_another_device will become another facet of the existing mirror and you can still read and write to it perfectly normally, with the difference that all changes will be seen and reflected in/from all the other mirror facets.
