====== ZFS - Structure - zpool ======

The zpool is the uppermost ZFS structure.

  * A zpool contains one or more vdevs, each of which in turn contains one or more devices.
  * Zpools are self-contained units.
    * One physical computer may have two or more separate zpools on it, but each is entirely independent of any others.
  * Zpools cannot share vdevs with one another.

ZFS redundancy is at the vdev level, not the zpool level.

  * There is absolutely no redundancy at the zpool level.
  * If any storage vdev or SPECIAL vdev is lost, the entire zpool is lost with it!

Modern zpools can survive the loss of a CACHE or LOG vdev.

  * They may lose a small amount of dirty data, if they lose a LOG vdev during a power outage or system crash.

A zpool is not a funny-looking RAID0.

  * It is a funny-looking JBOD, with a complex distribution mechanism subject to change.