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Configuring Power Supply Redundancy (CLI Procedure)

By default, the power management feature in EX8200 switches is configured to manage the power supplies for N+1 redundancy, in which one power supply is held in reserve for backup if any one of the other power supplies is removed or fails.

You can configure power management to manage the power supplies for N+N redundancy. For example, to set up your AC power supplies for dual power feed, N+N redundancy is required. In N+N redundancy, power management allocates half of the online power supplies to normal operating power and half to redundant power. If you have an odd number of online power supplies, power management allocates one more power supply to normal operating power than to redundant power.

This topic describes how to configure power management for N+N redundancy and how to revert back to N+1 redundancy if your deployment needs change.

Before you configure power management for N+N redundancy, ensure that you have sufficient power supplies to meet the power requirements of this configuration. Use the show chassis power-budget-statistics command to display your current power budget.

Note: To allow more power to be available to line cards, power management compensates for the reduced normal operating power in an N+N configuration by reserving less power to the chassis than it does in an N+1 configuration. For the EX8208 switch, the power reserved for the chassis is reduced to 1200 W from 1600 W. For the EX8216 switch, it is reduced to 1800 W from 2400 W. In determining whether you have enough power for an N+N configuration, take this reduction of reserved chassis power into account.

The reduction in reserved chassis power is achieved by reducing the maximum fan speed to 60 percent in an N+N configuration from 80 percent in an N+1 configuration. Because the maximum fan speed is reduced, it is possible that a line card that overheats would be shut down sooner in an N+N configuration than in an N+1 configuration.

To configure N+N redundancy:

[edit chassis]
user@switch# set psu redundancy n-plus-n 

To revert back to N+1 redundancy:

[edit chassis]
user@switch# delete chassis psu redundancy n-plus-n

Published: 2010-04-13

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