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Fan Modules Run Rapidly After an RH2285 Is Powered On

Publication Date:  2018-09-05 Views:  325 Downloads:  0
Issue Description
Hardware configuration: RH2285 server

Software configuration: no requirement

Symptom: After the RH2285 is powered on, the fan modules run rapidly.
Alarm Information
a. Run the ipmctool 2 command on the BMC CLI, and the displayed fan speed is 100%.

b. Run the top command on the BMC CLI, and the command output shows that the bmcipmi.out and webs processes have high CPU usage.
Handling Process
You can select one of the following solutions, where solution 1 is recommended.

1. Manually copy the rh2285_*disk_sdr.bin file from the /data/mgnt/ directory to the /data/ directory. If the server has eight hard disks, copy the rh2285_8disk_sdr.bin file. If the server has 12 hard disks, copy the rh2285_12disk_sdr.bin file. Change the file name to rh2285sdr.bin or rh1285sdr.bin based on the server type. Run the reboot command on the BMC CLI to reset the BMC.

2. Use a jumper cap to forcibly turn the RH2285 into the RH1285, and power on the server. After the OS is powered on, power off the server, remove the jumper cap, and then power on the server.
(Insert a jumper cap on the second pair of pins counted inwards from J76. The third pair of pins is the switch between the BMC and the system serial port. If a jumper cap is inserted on the third pair of pins, the BMC serial port is used. Otherwise, the system serial port is used.)

3. Upgrade the BMC software on the CLI. For details, see the upgrade guide.

For example (assuming that the server is an RH2285 with 12 hard disks):
1. The /data/mgnt directory of the BMC has all types of sdr files (including files for 4-disk, 8-disk, and 12-disk) of the rack server.
2. For the RH2285 with 12 hard disks, copy the rh2285_12disk_sdr.bin file to the /data/ directory.
3. After the file is coped to the new directory, rename the /data/rh2285_12disk_sdr.bin file as rh2285sdr.bin.
4. Reset the BMC for the changes to take effect, and the fan speed is recovered.
Root Cause
The output of the top command shows that the webs and bmcipmi.out processes keep being delivered without interruption, indicating that exceptions exist.

Past experience of resolving similar problems indicates that the webs process fails to obtain the sdr information.

On the BMC CLI, run the ls –al /data/ command. The command output shows that the sizes of the rh2285sdr.bin file and the rh1285sdr.bin file are zero. (In B031 and later versions, the sdr file command is changed to sdr0.bin.)
Run the ls -al /data/ command. The command output shows that the size of the rh2285sdr.bin file is zero (for the RH2285).
Run the ls -al /data/ command. The command output shows that the size of rh1285sdr.bin file is zero (for the RH1285).

The sdr file is empty. Therefore, modules including the fan modules cannot be initialized, and fan speed settings do not take effect.
To resolve problems related to high fan speed, run the ipmctool 2 and ipmctool 3 commands on the BMC CLI to check the fan speed.

Then run the ipmcget -d healthevent command to check the health status of the BMC system and determine whether alarms for other components are generated.

If the preceding method works, the fan modules run at a normal speed a short period after the BMC is reset. The fan speed change can be identified based on the fan noise.