Using The Power And Thermal Features; Server Power-On; Brownout Recovery; Graceful Shutdown - NEC iLO 5 User Manual

11.

Using the power and thermal features

Server power-on

If an AC power loss occurs on a Express server with iLO 5, approximately 30 seconds must elapse
before the server can power on again. If the power button is pressed during that time, it will
blink, indicating a pending request.
This delay is a result of the iLO firmware loading, authenticating, and booting. iLO processes
pending power-button requests when initialization is complete. If the server does not lose
power, there is no delay. A 30-second delay occurs only during an iLO reset. The power button is
disabled until iLO is ready to manage power.
The iLO firmware monitors and configures power thresholds to support managed-power
systems (for example, using power capping technology). Multiple system brownout, blackout,
and thermal overloads might result when systems are allowed to boot before iLO can manage
power. The managed-power state is lost because of AC power loss, so iLO must first boot to a
restore state and allow power-on.

Brownout recovery

A brownout condition occurs when power to a running server is lost momentarily. Depending on
the duration of the brownout and the server hardware configuration, a brownout might
interrupt the operating system, but does not interrupt the iLO firmware.
iLO detects and recovers from power brownouts. If iLO detects that a brownout has occurred,
server power is restored after the power-on delay unless Auto Power-On is set to Always
Remain Off. After the brownout recovery, the iLO firmware records a Brown-out recovery event
in the iLO Event Log.

Graceful shutdown

The ability of the iLO processor to perform a graceful shutdown requires cooperation from the
operating system. To perform a graceful shutdown, the iLO driver and
ESMPRO/ServerAgentService or Agentless Management Service must be loaded. iLO
communicates with the driver and above service and uses the appropriate operating system
method of shutting down the system safely to ensure that data integrity is preserved.
If the driver and above service is not loaded, the iLO processor attempts to use the operating
system to perform a graceful shutdown through the power button. iLO emulates a physical
power-button press (iLO momentary press) to prompt the operating system to shut down
gracefully. The behavior of the operating system depends on its configuration and settings for a
power-button press.
The Thermal Shutdown option in the UEFI System Utilities allows you to disable the automatic
shutdown feature. This configuration allows the disabling of automatic shutdown except in the
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