System Administration Guide: Virtualization Using the Solaris Operating System

Sparse Root Zones

Non-global zones that have inherit-pkg-dir resources are called sparse root zones. On OpenSolaris 2006.09, sparse root zones are native branded zones. See the native(5) man page for more information on these types of branded zones.

The sparse root zone model optimizes the sharing of objects in the following ways:

In this model, all packages appear to be installed in the non-global zone. Packages that do not deliver content into read-only loopback mount file systems are fully installed. There is no need to install content delivered into read-only loopback mounted file systems since that content is inherited (and visible) from the global zone.

An additional 40 megabytes of RAM per zone are suggested, but not required on a machine with sufficient swap space.