System Administration Guide: Oracle Solaris Containers-Resource Management and Oracle Solaris Zones

Sparse Root Zones

In the Solaris 10 release, non-global zones that have inherit-pkg-dir resources are called sparse root 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.