Cisco WS-SUP32-GE-3B Software Configuration Guide - Page 810

Understanding How Power Management Works Chapter 50 Power Management and Environmental Monitoring The modules have different power requirements, and some configurations require more power than a single power supply can provide. The power management feature allows you to power all installed modules with two power supplies. However, redundancy is not supported in this configuration because the total power drawn from both power supplies is at no time greater than the capability of one supply. Redundant and nonredundant power configurations are described in the following sections. To determine the power requirements for your system, see the "Determining System Power Requirements" section on page 50-5. Enabling or Disabling Power Redundancy To disable or enable redundancy (redundancy is enabled by default) from global configuration mode, enter the power redundancy-mode combined | redundant commands. You can change the configuration of the power supplies to redundant or nonredundant at any time. To disable redundancy, use the combined keyword. In a nonredundant configuration, the power available to the system is the combined power capability of both power supplies. The system powers up as many modules as the combined capacity allows. However, if one power supply fails and there is not enough power for all of the previously powered-up modules, the system powers down those modules. To enable redundancy, use the redundant keyword. In a redundant configuration, the total power drawn from both power supplies is not greater than the capability of one power supply. If one supply malfunctions, the other supply can take over the entire system load. When you install and power up two power supplies, each concurrently provides approximately half of the required power to the system. Load sharing and redundancy are enabled automatically; no software configuration is required. To view the current state of modules and the total power available for modules, enter the show power command (see the "Viewing System Power Status" section on page 50-4). Table 50-1 describes how the system responds to changes in the power supply configuration. Table 50-1 Effects of Power Supply Configuration Changes Configuration Change Redundant to nonredundant Nonredundant to redundant (both power supplies must be of equal wattage) Equal wattage power supply is inserted with redundancy enabled Effect • System log and syslog messages are generated. • System power is increased to the combined power capability of both power supplies. • Modules marked power-deny in the show power oper state field are brought up if there is sufficient power. • System log and syslog messages are generated. • System power is decreased to the power capability of one supply. • If there is not enough power for all previously powered-up modules, some modules are powered down and marked as power-deny in the show power oper state field. • System log and syslog messages are generated. • System power equals the power capability of one supply. • No change in module status because the power capability is unchanged. 50-2 Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY OL-11439-03