Ns7 System With Rack-Mounted Ups And Data Center Ups In Parallel - HP Integrity NonStop X NS7 Planning Manual

NS7 System With Rack-Mounted UPS and Data Center UPS in Parallel

Figure 25 shows an example of a non-supported configuration in a NS7 system with the left
PDUs connected to the rack-mounted UPS and the right PDUs connected to the data center
UPS. In this configuration, OSM manages and monitors the rack-mounted UPS. However, OSM
does not manage or monitor the data center UPS.
Figure 25 NS7 System With Rack-Mounted UPS and Data Center UPS in Parallel
When the utility power fails, OSM detects a UPS AC Input not Present event from the
rack-mounted UPS. OSM does not recognize the data center UPS. OSM does not detect that
the data center UPS is running on battery and that the UPS has entered its battery runtime. OSM
does not initiate the controlled shutdown of the I/O operations and processors.
The rack-mounted UPS shuts down before the data center UPS.
If the utility power is not restored before the data center UPS shuts down, any data in the
NS7 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+).
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.
Non-Supported UPS Configurations 89