Ns7 System With A Data Center Ups, Single Power Rail - HP Integrity NonStop X NS7 Planning Manual

NS7 System With a Data Center UPS, Single Power Rail

Figure 23 shows an example of a non-supported configuration in a NS7 system with the left
PDUs directly connected to the utility power and the right PDUs connected to the data center
UPS. In this configuration, OSM does not manage or monitor the data center UPS.
Figure 23 NS7 System With a Data Center UPS, Single Power Rail
When the utility power fails, OSM does not detect that the data center UPS is running on battery
and the UPS has entered its battery runtime. OSM does not initiate the controlled shutdown of
the I/O operations and processors.
If the utility power is not restored before the data center UPS shuts down, any data in the
NonStop X system disk drive write cache that has not been transferred to the disk drive media
is lost.
To prevent data loss during a utility power failure, you must manually disable the Write Cache
Enable (WCE) option on all the disk drive volumes. For information on the WRITECACHE disk
attribute and how to disable WCE, see the SCF Reference Manual for the Storage Subsystem
(G06.28+, H06.05+, J06.03+, L15.02+).
When the utility power is restored, you can enable the WCE.
During the utility power failure, the system can continue to run until the data center UPS
runs out of power or until it shuts down.
86 UPS and Data Center Power Configurations