On 18/02/2012 10:44, Da Rock wrote:

Your statement here makes some assumptions about the way ZFS works which aren't the case.

ZFS doesn't have partitions in the sense of areas of disk space reserved for a particular filesystem.

It has two concepts: the zpool and the zfs.

The zpool is about the collection of hardware used to provide the disk space. This incorporates all of the ideas about mirroring or RAIDZx or log devices of various types or spare drives. (Essentially what you'ld otherwise get from a very expensive raid controller.)

The zfs is a chunk of filesystem namespace designated for a specific purpose. You can use a zfs as a raw partition, but it is very much more common for it to be used as a filesystem.

zfses look quite a lot like partitions, but they are really quite fundamentally different. The basic storage unit used by ZFS is a 128kB block. The blocks used by a particular zfs can appear anywhere on the zpool, and unless the ZFS has been administratively limited to a particular size, the free space available to the zfs is exactly the free space available on the entire zpool.

Looked at that way, you can see it as essentially one big partition spanning the entire zpool.