NonStop NS14000 Planning Guide (H06.10+)

continue operation for a short period in case the power outage was only a momentary transient.
One or two ERMs installed in each cabinet can extend the battery-supported system runtime.
The system user must configure the system ride-through time to execute an orderly shutdown
before the UPS batteries are depleted. The time available for battery support depends on the
charge in the batteries and the power that the system draws.
Additionally, if the site’s air conditioning shuts down in a power failure, the system should be
shut down before its internal air temperatures can rise to the point that initiates a thermal
shutdown. A timely and orderly shutdown prevents an uncontrolled and asymmetric shutdown
of the system resources from depleted UPS batteries or thermal shutdown.
If a user-supplied rackmounted UPS or a site UPS is employed rather than the HP model R5500
XR UPS, the system is not notified of the power outage. The user is responsible for detecting
power transients and outages and developing the appropriate actions, which might include a
ride-through time based on the capacity of the site UPS and the power demands made on that
UPS.
The optional Model R5500 XR UPS and ERM installed in modular cabinets do not support any
devices that are external to the cabinets. External devices can include Fibre Channel tape drives,
external disk drives, LAN routers, and SWAN concentrators. Any external peripheral devices
that do not have UPS support will fail immediately at the onset of a power failure. Plan for UPS
support of any external peripheral devices that must remain operational as system resources.
This support can come from a site UPS or individual units as necessary.
This information relates to handling power failures:
• For ride-through time, see the SCF Reference Manual for the Kernel Subsystem.
• For the TACL SETTIME command, see the TACL Reference Manual.
• To set system time programmatically, see the Guardian Procedure Calls Reference Manual.
AC Power-Fail States
These states occur when a power failure occurs and an optional HP model R5500 XR UPS is
installed in each cabinet within the system:
NonStop operating system is running normally.NSK_RUNNING
OSM has detect a power failure and begins timing the
outage. AC power returning terminates RIDE_THRU and
puts the operating system back into an NSK_RUNNING
state. At the end of the predetermined RIDE_THRU time,
if AC has not returned, OSM executes a PFAIL_SHOUT
that results in the system going to LOW_POWER.
RIDE_THRU
Normal halt condition. Halted processors do not
participate in power-fail handling. A normal power-on
also puts the processors into the HALTED state.
HALTED
Halted-state services (HSS) informs the NonStop Blade
Element that it is in LOW_POWER state and then waits
until the NonStop Blade Element removes optic power.
LOW_POWER
Loss of optic power from the NonStop Blade Element
occurs, or the UPS batteries suppling the NonStop Blade
Element modules are completely depleted. When power
returns, the system is essentially in a cold-boot condition.
POWER_OFF
122 Control, Configuration, and Maintenance Tools