User guide

Introduction
System power in the Compaq RA4000 does not shut off completely with the
power switch. The two positions of the front panel power switch should be
considered as ON and STANDBY, rather than ON and OFF. The STANDBY
position removes power from most of the electronics and the drives, but
portions of the power supply and some internal circuitry remain active.
Consequently, to remove all power from the system, you must disconnect the
power cord from the storage system. In systems with multiple power supplies,
you must disconnect all the power cords to remove power completely from the
system.
To reduce the risk of electric shock or damage to the equipment,
disconnect power from the storage system by unplugging all power cords from
either the electrical outlet or the storage system.
The Compaq RA4000 has provisions for adding a second power supply, which
acts as a redundant supply when it is installed. The redundant power supply is
identical to the primary supply and shares the electrical load equally. If either
supply should fail or be removed, the other supply takes over the full load
without interruption. Hot-pluggability permits replacing the failed supply
without shutting the system down.
The Redundant Power Supply can be installed by the user at any time by
simply plugging it in to the storage system. No tools are needed and there is no
need to bring the system down. See Chapter 5, “Installing the Redundant
Power Supply Option” for more information on installing and using this
option.