Specifications

In the event of an individual fan failure, an SNMP trap and event log entry is generated. A system can typically

operate for quite a long time with a single fan failure (out of the eight), as the remaining fans can increase

speed to compensate for the loss of airflow.

The fan tray replicates the Power, Fan, Fault, and Locator LEDs found on the connectivity side of the 6600

switch. This is useful when attempting to locate a 6600 switch while servicing the product from either the hot- or

cold-aisle side of the equipment cabinets.

Figure 5: HP ProCurve 6600 Switch Fan Tray (J9271A)

Monitoring airflow direction

The “fan-pref-airflow-dir” CLI command registers the preferred airflow direction (front to back or back to front)

in the 6600 switch’s configuration file. Because the fan tray is mechanically reversible, it’s important for users

to monitor when fan hardware configuration does not match the desired configuration that is registered in the

configuration file. This notification is especially important when replacing a fan tray in a serviceable event. It

is important to note that the “fan-pref-airflow-dir” command does not change the airflow direction—it must be

reversed mechanically. The following sequence details CLI output from a 6600-24G switch where the “fan-pref-

airflow-dir” command has been entered:

ProCurve Switch 6600ml-24G# sh system fan

 fan-pref-airow-dir

fans

ProCurve Switch 6600ml-24G# sh system fans

Fan Information:

Num State AirowDirection Failures

Sys-1 Fan Ok Power To Port 0

*UserpreferredfanairowdirectionisPorttoPower

ProCurve Switch 6600ml-24G# shsystemfan-pref-airow-dir

 Preferredfanairowdirection:PortToPower

To illustrate the usefulness of the “fan-pref-airflow-dir” command, by default the 6600 switches ship from

the factory configured with back-to-front (power side to port side) cooling, with the intention that top-of-rack

switches would more likely have their network ports facing toward the back (hot aisle) of the cabinet to facilitate

server connectivity. With this intention, the default configuration for the command is, “Power-to-Port”, so the

“fan-pref-airflow-dir” command will not show up in the configuration file—it is the default.

If the user intends to change the airflow so that the preferred direction is Ethernet ports facing the cold aisle,

then in the configuration file the use should change the preferred direction to be port to power.

Upon change, the user would see:

» Log Entry/Syslog event

» And the “*” and message in the “show system fans” output

If the physical setup of the fans did not match this configured parameter—that is, it is there so that if someone

forgot to reverse the fans and you configured this preference, the user would receive a warning.