On Apr 2, 2011, at 5:28 PM, Dawid Horacy Golebiewski <dawid.golebiewski at tu-harburg.de> wrote: > I pondered Solaris for some time, but as I do not intend to build the OS > "from scratch" and nexenta was to GUIed for me I started researching SME. > What puzzled me is the theory and the practice: RAIDz is the best > solution from a theoretical standpoint (maximum features available) but > still raid 5,65+0 etc. are used. Why? Raidz/2/3 isn't raid5/6, similar but not the same. In ZFS you create vdevs, which can be individual disks, mirrors or raidzs. Then you create a pool out of multiple vdevs. The vdevs should be of the same size and type for performance and capacity planning reasons, but it's not a requirement. Currently you cannot add drives to a vdev, but you can add vdevs to a pool. IO written to a pool does round robin across the vdevs giving a raid0 type performance. -Ross