The root file system hierarchy is almost identical to systems that are running Oracle Solaris 10 with a ZFS root file system. A ZFS root pool contains a ZFS file system with separate directories of system-related components, such as etc, usr, and var, that must be available for the system to function correctly.
After you install a system, the root of the Oracle Solaris file system is mounted, which means files and directories are accessible.
All subdirectories of the root file system that are part of the Oracle Solaris OS, with the exception of /var, must be contained in the same file system as the root file system.
A separate /var file system is created automatically for a global zone and a non-global zone in Oracle Solaris 11.
Starting with Oracle Solaris 11.1, a rpool/VARSHARE file system is mounted at /var/share by default. The purpose of this file system is to share file systems across boot environments so that the amount of space that is needed in the /var directory for all BEs is reduced.
# ls /var/share audit cores crash mail
Symbolic links are automatically created from /var to the /var/share components previously listed for compatibility purposes. This file system generally requires no administration except to ensure that /var components do not fill up the root file system. During a system upgrade, it might take some time to migrate data from the original /var directory to the /var/share directory.
In addition, all Oracle Solaris OS components must reside in the root pool, with the exception of the swap and dump devices.
A default swap device and a dump device are automatically created as ZFS volumes in the root pool when a system is installed. You cannot use the same volume for both swap and dump devices. Also, you cannot use swap files in a ZFS root environment. See Swap and Dump Device Configuration Changes.