It should be noted that there is no longer any such thing as a "sparse" zone. Each zone has its own ZFS root filesystem, and a ZFS tree under that. They no longer share the root filesystem of the global zone, although they may have a clone of the global root filesystem. This is similar to, yet different from, the old style of sharing the /usr filesystem as read-only. The similarity resides in the fact that, if no changes are made, you only take up one zone's worth of filesystem space. The differences are rather critical however; changes made in the original are not reflected in any clones. Furthermore, the clones are writable, rather than read-only by default. However, it is possible to set a zone to have an "immutable" root. See Chapter 8, Security Improvements, for more details.

The zone-specific root filesystem is usually contained under:

$(zonepath)/rpool/ROOT

Because of this, it is also possible (and in a way, mandatory) to run beadm for zones. More details on...