NonStop NS2200 Series Planning Guide

SAS Disk Enclosures With a Rack-Mounted UPS
In this supported configuration, only SAS Disk Enclosures are protected by the rack-mounted UPS.
The rack(s) with SAS Disk Enclosures and/or Storage CLIMs are supported by one or more
rack-mounted UPS.
Figure 61 shows an example of a supported configuration in a NonStop system with the left PDUs
connected to the rack-mounted UPS, and the right PDUs connected to the utility power. The
rack-mounted UPS is connected to the utility power.
Figure 61 SAS Disk Enclosures With a Rack-Mounted UPS
When the utility power fails, the NonStop system powers off without an OSM-initiated controlled
shutdown of the I/O operations and processors. Only the products in the rack with the rack-mounted
UPS remain powered on. All completed disk write transactions’ data are written to the disk drive
media or the disk drive write cache. The rack-mounted UPS provides the extended time for the disk
drives to transfer the data from their write cache to the media. The rack-mounted UPS provides
extended time for the disk drives to transfer the data from their write cache to the media preventing
loss of data.
Supported UPS Configurations 201