FastIron Hardware Installation Guide for the FSX, FSX 800, and FSX 1600
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© 2008 Foundry Networks, Inc.
December 2008
A FastIron chassis can be either 1 + 1 redundant or N + 1 redundant.
1 + 1 redundancy
implies that for every
power supply, there is another redundant (backup) power supply. In other words, half of the supplies in the system
can fail, and the system will still operate normally.
N + 1 redundancy
implies that there is one redundant power
supply for N power supplies, where N is a number greater than one. For example, 3 + 1 redundancy means that in
a system with four power supplies, the system will continue to operate normally if one power supply fails, but will
not operate if more than one power supplies fail.
Power consumption is equally distributed (within a certain percentage depending on power load or power supply
type) among all power supplies in the system. When a power supply fails, the power load is redistributed equally
among the remaining power supplies. Note that power consumption between POE and System power supplies is
not shared, meaning loss of a System power supply does not impact a POE power supply, and vice versa.
What Happens When One or More System Power Supplies Fail
If one or more System power supplies fail and the system is left with less than the minimum number of power
supplies required for normal operation, the power supplies will go into overload and the system will start to shut
down. Several things can happen. The output voltage of the remaining good power supplies will likely drop as
they try unsuccessfully to generate more power than they are capable of. The system will react to a drop in
voltage by increasing the current draw. The hardware will shut down due to over-current protection or under-
voltage protection, whichever takes place first. One by one, the interface modules will shut down until the power is
within the power budget of the remaining power supplies. There is no particular order in which the interface
modules will shut down, as this will occur in hardware and not in software. The management CPU requires power
as well, and may also shut down during a power supply failiure.
After a power loss, if the system is left with less than the minimum number of power supplies required for normal
operation, the system will be left in an unknown state. At this point, manual recovery is required (i.e. restore power
and power cycle the chassis).
What Happens When One or More POE Power Supplies Fail
If one or more POE power supplies fail and the system is left with less than the minimum number of POE power
supplies, the POE power supplies will go into overload. Non-POE functions will not be impacted, provided the
System power supplies are still up and running. Several things can happen with a POE power supply failure. The
output voltage of the remaining good power supplies will likely drop as they try unsuccessfully to generate more
power than they are capable of. The system will react to a drop in voltage by increasing the current draw. The
hardware will shut down POE function due to over-current protection or under-voltage protection, whichever
occurs first. The interface modules will start to shut down its POE ports one by one until the over-power is within
the power budget of the remaining power supplies. There is no particular order in which the POE ports will shut
down, as this occurs in hardware and not in software.
After a power loss, if the system is left with less than the minimum number of power supplies required for normal
operation, the system will be left in an unknown state. At this point, manual recovery is required (i.e. restore power
and power cycle the chassis).
Cooling System
The cooling system is contained within the system’s fan tray assembly and modules. The following components
comprise the cooling system:
•
The FSX and FSX 800 each have six five-speed fans.
NOTE:
Starting with release 03.0.00, the fans operate at four speeds instead of five speeds.
•
The FSX 1600 has two five-speed fans in the rear of the chassis.
•
One fan control module. The fan control module maintains the power to the fans, and controls the fan speed
and the reporting of the fan status to the management module.
•
Two temperature sensors on each management module, and one temperature sensor on each interface
module
•
One temperature sensor on each switch fabric module (FSX 800 and FSX 1600 only).
The fan tray in the FSX and FSX 800 chassis is located in the right side of each chassis. The FSX 1600 has two
fan trays which are located in the top rear of the chassis.
