Oracle Solaris is designed to run continuously so that the electronic mail and network software can work correctly. However, some system administration tasks and emergency situations require that the system be shut down to a level where you can safely turn off power. In some cases, the system needs to be brought to an intermediate level, where not all system services are available.
Such cases include the following:
Adding or removing hardware
Preparing for an expected power outage
Performing file system maintenance, such as a backup
For information about using your system's power management features, see the poweradm(1M) man page.