Installation Guide

222 Brocade MLX Series and Brocade NetIron XMR Installation Guide
53-1004195-02
Managing the cooling system
Changing temperature thresholds for modules and fan speeds
The cooling system includes fans that operate at four speeds: low, medium, medium-high, and high. In general, each fan speed, (except
for low), has a low and high temperature threshold associated with it, as shown in Figure 152. The low fan speed has a high temperature
threshold only.
NOTE
Adjusting fan controls out of the default setting can negatively affect the efficient cooling of blades and may cause a blade to
overheat and shutdown.
FIGURE 152 Fan speeds and temperature thresholds
The low and high temperature thresholds allow the router to determine the speed at which the fans should operate. In general, the fans
operate according to these guidelines:
• If the temperature of all modules falls between the low and high thresholds for a fan speed, the fan continues to operate at that
speed.
• If the temperature of a management module, switch fabric module, or one interface module exceeds the high threshold specified
for a fan speed, the fan changes to the next higher speed. If the temperature of any of the modules exceeds the high threshold
for the high speed, the router shuts down the modules to prevent damage. The router also sends a warning message to the
system log and an SNMP trap. For information about viewing the warning messages, refer to “Displaying temperature warnings”
on page 229.
• The frequency with which the temperature is checked is determined by the setting of the temp-poll-period command. For
information about temp-poll-period command, refer to “Changing the temperature polling interval” on page 228.
• If the temperature of a management module, switch fabric module, and interface modules falls below the low threshold for a fan
speed, the fan changes to the next lower speed. If the temperature of all modules falls below the high threshold for the low speed,
the fan operates at the low speed.
• Table 37 describes default low and high temperature thresholds for each module and fan speed for Brocade MLX and NetIron
XMR routers.
TABLE 37 Default temperature thresholds for modules and fan speeds for Brocade MLX and NetIron XMR devices
Fan speed Low temperature threshold High temperature threshold
Management modules
High 77 C85C
Medium-high 67C80C
Medium 57C70C
Low –1 60C
Management modules CPU
High 75 C95C
Medium-high 65C80C
Operating
Temperature
Medium
Speed
Low Speed
Med-High
Speed
High
Speed
50 55 60 65 70 75 80 85 90 95
High, 60 deg.
Low 57, deg. High, 70 deg.
Low, 67 deg. High, 80 deg.
Low, 77 deg. High, 85 deg.