3Com VCX V7000 Maintenance Manual page 131

Adding UPS Support to an Existing VCX System 131
devices are used to provide power. For servers with redundant
power supplies, ensure that each power supply is connected to a
different UPS (and if possible, you should connect each UPS to
different mains circuits). In this case, the servers should all remain
operational unless both UPS devices are on battery and at or below
the low battery threshold. At this point, a coordinated shutdown
of all systems must be performed.
Figure 3 Two UPS Devices Powering Two VCX Servers
VCX Server
UPS
UPS
VCX Server
In this case, you designate one of the VCX servers as the master for
both UPS devices and any other VCX servers in the system as
slaves. When configuring the master, you identify the additional
UPS device by specifying its IP address.
If your VCX system includes multiple UPS devices, the servers do
■
not have redundant power supplies, and the primary and
secondary servers (of any configuration type) are co-located, then
you should assign the primary and secondary servers of a given
configuration type to different UPS devices (see Figure 4).
For example, if you have a regional VCX system that has a primary
IP Messaging Server and a secondary IP Messaging Server (plus
other VCX servers) and you are using two UPS devices to power all
the servers, put the primary IP Messaging Server on one UPS and
the secondary IP Messaging Server on the other UPS. This reduces
the possibility of a single failure disrupting IP Messaging service
availability.