NonStop NS1000 Planning Guide (H06.08+)

A rack-mounted UPS can often supply five minutes of power with some extra capacity for
contingencies, provided the batteries are new and fully charged. This five minute figure is an
estimate used for illustration in this discussion, not a guarantee for any specific configuration.
You must ensure that the battery capacity for a fully-powered system allows for at least two
minutes after OSM initiates the orderly shutdown to allow the disk cache to be flushed to
nonvolatile media. Assuming the UPS has five minutes of power capacity, you would set the
ride-through time for three minutes (UPS capacity of five minutes minus two minutes for OSM).
Power can be extended by adding ERMs to the configuration; and power for UPS alone can
extend beyond five minutes based on power consumption. To extend the ride-through time
beyond three minutes, use this manual and your UPS documentation to calculate the expected
power consumption, measure the site power consumption, factor in the ERM, if present, and
make adjustments. Also consider air conditioning failures during a real power failure because
increased ambient temperature typically causes the fans to run faster, which causes the system
to draw more power. By allowing for the maximum power consumption and applying those
figures to the UPS calculations provided in the UPS manuals, you can increase the ride-through
time beyond three minutes.
Considerations for Site UPS Configurations
OSM cannot monitor a site UPS. The SCF configured ride-through time on a NonStop NS1000
system has no effect if only a site UPS is used. With a site UPS instead of a rack-mounted UPS,
the customer must perform manual system shutdown if the backup generators cannot be started.
It is also possible to have a rack-mounted UPS in addition to a site UPS. Since the site UPS can
supply a whole computer room or part of that room, including required cooling, from the
perspective of OSM, site UPS power can supply the group 100 AC power. The group 100 UPS
power configured in OSM, in this case, would still come from a rack-mounted UPS (one of the
supported models).
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:
DescriptionSystem State
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 blade element
that it is in LOW_POWER state and then waits until optic
power to the blade element is removed.
LOW_POWER
Loss of optic power from the blade element occurs, or the
UPS batteries suppling the blade elements are completely
depleted. When power returns, the system is essentially
in a cold-boot condition.
POWER_OFF
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