See my blog on this topic:
http://blogs.sun.com/bill/entry/ditto_blocks_the_amazing_tape
The quick summary is that if there is more than one vdev comprising the
pool, the copies will be spread across multiple vdevs. If there is only
one, then the copies are spread out physically (at least by
The filesystem allows to keep two or more copies of the data written. What I'm
interested in to know is how the placement of the copies is done. Consider a
JBOD pool, having set the filesystem to keep two copies, will the copies be
actively placed on two different volumes, as such allowing to su
