For others, I found this, explaining the process: http://alp-notes.blogspot.com/2011/09/adding-vdev-to-raidz-pool.html http://alp-notes.blogspot.com/2011/09/add

For others, I found this, explaining the process: http://alp-notes.blogspot.com/2011/09/adding-vdev-to-raidz-pool.html http://alp-notes.blogspot.com/2011/09/adding-vdev-to-raidz-p... Downside is, you lose a significant chunk of storage (the author measured > 20%), but you can add new storage to a pool online.