The lumount command mounts all the boot environment's file systems. If you do not explicitly specify a mount point, lumount creates a mount point that uses the boot environment name, rather than a random set of numbers. This change prevents a proliferation of mount points and aids in using the luumount command.
Here is an example of the old and new mount point naming:
Mount point name with a number identifier: /.alt.1234
Mount point name with the boot environment name as the identifier: /.alt.solaris8.
In this example, the boot environment name is solaris8.
The luumount command unmounts the boot environment's root file system. The luumount command now accepts a mount point as well as the boot environment name. And with the -f option, a boot environment's file system can be forcibly unmounted.
See the man pages, lumount(1M) and luumount(1M).