If you're a sysadmin and managing remotely Linux servers, every now and then if a machine is hanging without a reason it useful to check the server Power Supply state. I say that because often if the machine is mysteriously hanging and a standard Root Cause Analysis (RCA) on /var/log/messages /var/log/dmesg /var/log/boot etc. did not bring you to any different conclusion. The next step after you send a technician to reboot the machine is to check on Linux OS level whether Power Supply Unit (PSU) hardware on the machine does not have some issues.
As blogged earlier on how to use ipmitool to manage remote ILO remote boards etc. the ipmitool can also be used to check status of Server PSUs.
Below is example output of 2 PSU server whose Power Supplies are functioning normally.
[root@linux-server ~]# ipmitool sdr type "Power Supply"
PS Heavy Load | 2Bh | ok | 19.1 | State Deasserted
Power Supply 1 | 70h | ok | 10.1 | Presence detected
Power Supply 2 | 71h | ok | 10.2 | Presence detected
PS Configuration | 72h | ok | 19.1 |
PS 1 Therm Fault | 75h | ok | 10.1 | Transition to OK
PS 2 Therm Fault | 76h | ok | 10.2 | Transition to OK
PS1 12V OV Fault | 77h | ok | 10.1 | Transition to OK
PS2 12V OV Fault | 78h | ok | 10.2 | Transition to OK
PS1 12V UV Fault | 79h | ok | 10.1 | Transition to OK
PS2 12V UV Fault | 7Ah | ok | 10.2 | Transition to OK
PS1 12V OC Fault | 7Bh | ok | 10.1 | Transition to OK
PS2 12V OC Fault | 7Ch | ok | 10.2 | Transition to OK
PS1 12Vaux Fault | 7Dh | ok | 10.1 | Transition to OK
PS2 12Vaux Fault | 7Eh | ok | 10.2 | Transition to OK
Power Unit | 7Fh | ok | 19.1 | Fully Redundant
Now if you have a server lets say on an old ProLiant DL360e Gen8 whose Power Supply is damaged, you will get an from ipmitool similar to:
[root@linux-server systemd]# ipmitool sdr type "Power Supply"
Power Supply 1 | 30h | ok | 10.1 | 100 Watts, Presence detected
Power Supply 2 | 31h | ok | 10.2 | 0 Watts, Presence detected, Failure detected, Power Supply AC lost
Power Supplies | 33h | ok | 10.3 | Redundancy Lost
If you don't have ipmitool installed due to security or whatever but you have the hardware detection software dmidecode you can use it too to get the Power Supply state
[root@linux-server systemd]# dmidecode -t chassis
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.8 present.
Handle 0x0300, DMI type 3, 21 bytes
Chassis Information
Manufacturer: HP
Type: Rack Mount Chassis
Lock: Not Present
Version: Not Specified
Serial Number: CZJ38201ZH
Asset Tag:
Boot-up State: Critical
Power Supply State: Critical
Thermal State: Safe
Security Status: Unknown
OEM Information: 0x00000000
Height: 1 U
Number Of Power Cords: 2
Contained Elements: 0
To find only Power Supply info status on a server with dmideode.
# dmidecode –type 39
Plug between the power supply and the mainboard voltage / coms ATX specification
This can also be used on a normal Linux desktop PCs which usually have only 1U (one power supply) on many of Ubuntus and Linux desktops where lshw (list hardaware information) is installed to get the machine PSUs status with lshw
root@ubuntu:~# lshw -c power
*-battery
product: 45N1111
vendor: SONY
physical id: 1
slot: Front
capacity: 23200mWh
configuration: voltage=11.1V
Thermal State: Safe
Security Status: Unknown
OEM Information: 0x00000000
Height: 1 U
Number Of Power Cords: 2
Contained Elements: 0
Finally to get an extensive information on the voltages of the Power Supply you can use the good old lm_sensors.
# apt-get install lm-sensors
# sensors-detect
# service kmod start
# sensors
# watch sensors
As manually monitoring Power Supplies and other various data is dubious, finally you might want to use some centralized monitoring. For one example on that you might want to check my prior Zabbix to Monitor Hardware Hard Drive / Temperature and Disk with lm_sensors / smartd on Linux with Zabbix.
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Tags: broken, find, How to, hp, Linux Power Supply, linux?, log messages, power supply, Power Supply State Critical, PSU, state, Thermal State Safe, use, various