Specifications

ac power subsystem
requirements for fault-
tolerant power compliance
The HP Server rp8400 is one of only two midrange servers (the other is the 8-way HP Server
rp7410) to be certified with no deviations by The Uptime Institute under its Fault Tolerant Power
Compliance Specification.
The rp8400 hardware is capable of receiving ac input from two different ac power sources. The
objective is to maintain full equipment functionality when operating from power source A and
power source B, or from A alone or B alone. This capability is known as “fault-tolerant power
compliance.”
According to the Uptime Institute’s Site Uptime Network specification, for equipment to qualify as
being truly fault-tolerant power-compliant, it must meet all of the following criteria as initially
installed and as ultimately used in operation:
• If either one of two ac power sources fails or is out of tolerance, the equipment must still be able
to start up or continue uninterrupted operation with no loss of data or reduction in hardware
functionality, performance, capacity, or cooling.
• After the return of either ac power source from a failed or out-of-tolerance condition during
which acceptable power was continuously available from the other ac power source, the
equipment will not require a power-down, initial program load (IPL), or human intervention to
restore data, hardware functionality, performance, or capacity.
• The first or second ac power source can fail one second after the return of the first or second ac
power source from a lost or out-of-tolerance condition with no loss of data, hardware
functionality, performance, capacity, or cooling.
• The two ac power sources can be out of synchronization with each other, with different
voltages, frequencies, phase rotations, and phase angles, as long as the power characteristics
for each separate ac source remain within the range of the manufacturer’s published
specifications and tolerances.
• Both ac power inputs will terminate within the manufacturer’s equipment. Internal or external
active input switching devices (such as static transfer switches) are not acceptable.
• A fault inside the manufacturer’s equipment that results in the failure of one ac power source will
not be transferred to the second ac power source, causing it to also fail.
• An internal uninterruptible power system (UPS), internal power batteries (batteries for cache
memory are acceptable), or other type of energy storage equivalent is allowable only for the
purpose of a prompt, orderly shutdown. The existence and voltampere (VA) capacity of an
internal UPS or batteries and the time required for a prompt, orderly shutdown must be
identified.
• With both ac power inputs available, the power provided by each of the two internal power
trains will be 50% ± 10% of the power output for the supply.
• An external software alarm must be provided via the equipment’s software or the host’s
operating system when an ac power source is lost or is outside the manufacturer’s published
tolerances, and the software must also indicate when the abnormal condition is corrected.
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