These servers are equipped with redundant hot-swappable power supplies. With redundant power supplies, you can remove and replace a power supply without shutting the server down, provided that the other power supply is online and working.
The server offers two redundancy modes for the power supplies. Light load efficiency mode (LLEM) places PS1 in a warm standby condition while PS0 carries the entire load more efficiently by itself. If PS0 loses AC power or is extracted for replacement, PS1 takes over the load automatically. Some rare internal failures of PS0 could cause the server to lose power faster than PS1 can take over.Disabling the LLEM Policy causes the power supplies to share the load at all times, at the expense of efficiency during light loads. For information about configuration policies, refer to the SPARC T4 Series Servers Administration Guide and the Oracle ILOM documentation.
Caution - If a power supply fails and you do not have a replacement available, to ensure proper airflow, leave the failed power supply installed in the server until you replace it with a new power supply.