You can install and boot a ZFS root file system or migrate to a ZFS root file system in the following ways:
Install a ZFS root file system – Available starting in the Solaris 10 10/08 release.
Migrate from a UFS root file system to a ZFS root file system with Oracle Solaris Live Upgrade – You must have installed at least the Solaris 10 10/08 release or you must have upgraded to at least the Solaris 10 10/08 release.