Emergency Power Control - Hitachi COMPUTE BLADE 500 SERIES Management Module Setup Manual

Tip: We recommend that you use accurate power control (APC) as the power
capping function.
You cannot use DCMI to control the power of the entire chassis by using the
management module.
In addition, to use DCMI, server blades must support it.
Select an appropriate power capping function.
Note:
• You cannot enable DCMI (see
the same time. When you enable the DCMI mode, APC is automatically
disabled and you cannot change the settings related to APC.
• When you enable the DCMI mode, the APC settings are reset. Similarly,
when you disable the DCMI mode, the DCMI settings are reset.
• You can use DCMI and EPC simultaneously. If the power supply becomes
insufficient because of a power failure, power capping by EPC is prioritized
for continuous operation of the equipment.

Emergency power control

Emergency Power Control (EPC) function protects power supply modules
embedded in the system unit and your power equipment, such as circuit
breakers and power distribution units (PDU), from the power overload beyond
the maximum power capping value by the high speed power capping on the
server blades.
When the power overload is detected, EPC controls the power consumption
by reducing the processor frequency of server blade to its allowable minimum
value. The frequency reduction causes the performance suppression and the
status lasts one minute. When the power overload is detected twice within six
minutes, EPC reduces the processor frequency and then forces to change the
maximum power consumption by 90 % to reduce the performance
suppression. The forced setting is released one hour later when the power
does not exceed the maximum power consumption setting. The forced setting
is also released when the system unit AC power is turned off.
EPC enables you to set any value for maximum power consumption using the
facility capping function. The setting is not necessary when the maximum
power consumption for the system unit does not exceed the allowable
maximum power on the power facilities.
Hitachi Compute Blade 500 Series Management Module Setup Guide
Item
DCMI function on page
Functional detail
Description
in the server chassis have been initialized and
the main power is powered off.
The DCMI mode and the APC functionality are
mutually exclusive. Therefore, you cannot use
both at the same time.
2-228) and APC at
2-215