NonStop S-Series Operations Guide (G06.29+)

HP NonStop S-Series Operations Guide—522459-009
15-1
15
Power Failures: Preparation and
Recovery
When to Use This Section on page 15-1
How an Enclosure Responds to Power Failures on page 15-1
How External Devices Respond to Power Failures on page 15-2
With an Uninterruptible Power Supply (UPS) on page 15-2
Without an Uninterruptible Power Supply (UPS) on page 15-2
Preparing for Power Failure on page 15-3
Monitoring Power Supplies on page 15-3
Maintaining Batteries on page 15-3
Recharging Spare Batteries on page 15-3
Monitoring Batteries on page 15-3
Causes of Drained Batteries on page 15-3
Recharging Drained Batteries on page 15-4
Power Failure Recovery Operations on page 15-4
Procedure to Recover From a Power Failure on page 15-4
Setting System Time on page 15-5
Related Reading on page 15-5
When to Use This Section
Use this section for information about how to prepare for power failures and how to
recover if a power failure occurs.
How an Enclosure Responds to Power
Failures
Processor enclosures and I/O enclosures include a battery backup, whereas IOAM
enclosures do not. IOAM enclosures depend on the presence of an uninterruptible
power supply to accommodate power failures.
In the case of processor enclosures and I/O enclosures, the batteries in the enclosure
continue to operate all the components in the enclosure for a short, configurable period
of time, called the power-fail delay time. If the power failure lasts longer than the
power-fail delay time, the batteries maintain power to just the memory for as long as
they can, usually 45 minutes. The exact amount of time the batteries can maintain
memory depends on: