Varying ipmitool power supply values, real???

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mathog
Posts: 48
Joined: 2008/07/09 23:52:06

Varying ipmitool power supply values, real???

Post by mathog » 2017/12/22 22:53:25

It seems that on some Dell Poweredge servers ipmitool indicates that one redundant power supply is taking all the power
and the other none, whereas on other servers it shows the load being almost evenly divided, and on yet another example
there is some load on both, but it is far from balanced. All of these machines have two redundant power
supplies and in each example these are plugged into separate live 120V circuits. What accounts for all of this
variation??? Are the ipmitool numbers correct, and these machines do very different things with their redundant power supplies, or do the machines actually all balance power consumption and the ipmitool values are off in some cases? Not sure if this is a hardware issue, software issue, or some combination thereof. My best guess is that this is the result of one or more BIOS settings (of which these machines have many more than a typical PC).


Four examples:

Centos 6.9 machine (we have two servers of this type and they both do the same thing). Here the
power consumption doesn't make sense, because 118*.25 = 29.5 W, but the software says 112W.

Code: Select all

# dmesg | grep -i powere
DMI: Dell Inc. PowerEdge T320/0W7H8C, BIOS 1.5.1 03/08/2013
# ipmitool sdr list full
Inlet Temp       | 17 degrees C      | ok
Sys Fan1 RPM     | 600 RPM           | ok
Sys Fan2 RPM     | disabled          | ns
Current 1        | 0.25 Amps         | ok
Current 2        | 0 Amps            | ok
Voltage 1        | 118 Volts         | ok
Voltage 2        | 120 Volts         | ok
Pwr Consumption  | 112 Watts         | ok
Temp             | 41 degrees C      | ok
Temp             | disabled          | ns
Centos 7.0 machine, very similar machine to the first example above, but here the power is
shown as split between the two supplies. Indicated power consumption is close to .48*122 + .6*122 = 131.76

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# dmesg | grep -i powere
[    0.000000] DMI: Dell Inc. PowerEdge T310/0MNFTH, BIOS 1.8.2 08/17/2011
# ipmitool sdr list full
Temp             | disabled          | ns
Temp             | disabled          | ns
Temp             | disabled          | ns
Ambient Temp     | disabled          | ns
Ambient Temp     | disabled          | ns
Temp             | disabled          | ns
Ambient Temp     | 22 degrees C      | ok
Planar Temp      | disabled          | ns
FAN 1 RPM        | 1200 RPM          | ok
Current 1        | 0.48 Amps         | ok
Current 2        | 0.60 Amps         | ok
Voltage 1        | 122 Volts         | ok
Voltage 2        | 122 Volts         | ok
System Level     | 133 Watts         | ok
Centos 6.9. Again, it shows all the power coming from
one supply, but the power consumption is at least ballpark: 1.8 * 122 = 220W ~= 210W.

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# dmesg | grep -i powere
DMI: Dell Inc. PowerEdge T620/03GCPM, BIOS 2.2.2 01/16/2014
# ipmitool sdr list full
Fan1 RPM         | 1080 RPM          | ok
Fan2 RPM         | 1080 RPM          | ok
Fan3 RPM         | disabled          | ns
Fan4 RPM         | disabled          | ns
Fan5 RPM         | disabled          | ns
Fan6 RPM         | disabled          | ns
Inlet Temp       | 20 degrees C      | ok
Current 1        | 1.80 Amps         | ok
Current 2        | 0 Amps            | ok
Voltage 1        | 122 Volts         | ok
Voltage 2        | 126 Volts         | ok
Pwr Consumption  | 210 Watts         | ok
Temp             | 42 degrees C      | ok
Temp             | 48 degrees C      | ok
Final example, Centos 6.9, very similar to the preceding machine, but here
a little current is passed through one supply. We have two of these, with slightly different CPUs,
and they both do more or less the same thing with respect to the power supplies.
So not balanced, and not completely unused either.

Code: Select all

# dmesg | grep -i powere
DMI: Dell Inc. PowerEdge T630/0W9WXC, BIOS 1.5.4 10/04/2015
## other machine of this type shows
## DMI: Dell Inc. PowerEdge T630/0W9WXC, BIOS 1.2.10 03/10/2015
# ipmitool sdr list full
Fan1             | 960 RPM           | ok
Fan2             | 960 RPM           | ok
Fan3             | disabled          | ns
Fan4             | disabled          | ns
Fan5             | disabled          | ns
Fan6             | disabled          | ns
Inlet Temp       | 15 degrees C      | ok
CPU Usage        | 3 percent         | ok
IO Usage         | 0 percent         | ok
MEM Usage        | 0 percent         | ok
SYS Usage        | 4 percent         | ok
Current 1        | 1.60 Amps         | ok
Current 2        | 0.20 Amps         | ok
Voltage 1        | 118 Volts         | ok
Voltage 2        | 118 Volts         | ok
Pwr Consumption  | 187 Watts         | ok
Temp             | 63 degrees C      | ok
Temp             | 60 degrees C      | ok

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TrevorH
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Re: Varying ipmitool power supply values, real???

Post by TrevorH » 2017/12/23 01:34:06

Look in your iDRAC settings pages for the power policy. Dell allow you to configure the PSUs as redundant but they then default to having one run in active, one in standby mode. You need to change that to have them both active at the same time.
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mathog
Posts: 48
Joined: 2008/07/09 23:52:06

Re: Varying ipmitool power supply values, real???

Post by mathog » 2018/01/02 21:31:59

So it is real then. OK, that isn't a problem, I just wanted to know what was going on.

Thanks.

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