H3C出现如下报错信息:
[H3C]fan prefer-direction slot 1 power%Jan  1 04:30:13:401 2013 H3C DEV/1/FAN_DIRECTION_NOT_PREFERRED: Fan 1 airflow direction is not preferred on slot 1, please check it.
%Jan  1 04:30:13:404 2013 H3C DEV/1/FAN_DIRECTION_NOT_PREFERRED: Fan 2 airflow direction is not preferred on slot 1, please check it.

[H3C]%Jan  1 04:30:46:202 2013 H3C DEV/5/FAN_RECOVERED: Fan 1 recovered.
%Jan  1 04:30:46:207 2013 H3C DEV/5/FAN_RECOVERED: Fan 2 recovered.

解决办法：

检查交换机风扇配置信息发现交换机风扇的实际气流方向为：Airflow Direction: Port-to-power；而配置用户下看到风扇模块的优选气流方向为：Prefer Airflow Direction: Power-to-port，两者不一致（交换机风扇反转），导致交换机风扇状态为：FanDirectionFault，风扇信号灯告警，交换机SYS信号灯告警。
处理方法：
因为风扇模块的实际气流方向是无法改变的，只能去改变风扇模块的优选气流方向和风扇实际气流方向一致，操作步骤如下：

[SW]dis fan