6 ms·

The minimum viable fan control script

51 points by hddherman 4y ago

_wolfie_ 4y ago
> if ((temp > 90000)); then What is this syntax? I would have assume something like `[ $temp -gt 90000 ]` or `$((temp > 90000))`. Is the dollar here optional? Is this something bash specific?
- scbrg 4y ago
  > Is this something bash specific? Yes. http://mywiki.wooledge.org/ArithmeticExpression#Arithmetic_Commands http://mywiki.wooledge.org/ArithmeticExpression#Arithmetic_C...
buescher 4y ago
I was expecting a basic thermostat with hysteresis, but no, it's a stepwise proportional control. Your fan could very well wind up oscillating at one of the step transition points which is probably not great for the fan.
- zbrozek 4y ago
  Your sanity will suffer more than the fan.
  - buescher 4y ago
    Well, there's that, but the audience is people who will write their own fan control script...
- 10000truths 4y ago
  If this is a realistic failure mode, one would hope that there is some kind of rate-limiting at the firmware or driver level.
  - buescher 4y ago
    One would hope.
mortenlarsen 4y ago
There is no need to call cat to read from a file. > temp=$(cat /sys/class/thermal/thermal_zone1/temp) temp=$(</sys/class/thermal/thermal_zone1/temp)
- 0xCAP 4y ago
  A classic example of cat abuse in my book.
  - deeblering4 4y ago
    meow
  - elsyx 4y ago
    Definitely an unwarranted cat call.
- piperswe 4y ago
  IMO the cat version is more readable, and any performance difference should be negligible
XiS 4y ago
As an alternative, been using this PID fan control script to keep my HDDs cool for ages. https://forums.freenas.org/index.php?threads/pid-fan-controller-perl-script.50908/ https://forums.freenas.org/index.php?threads/pid-fan-control...
- francis-io 4y ago
  I've some a similar thing with my NAS on a Supermicro X10 (I think) on Linux. I have had all kinds of trouble getting quiet fans on this board under Linux. I think it's a mix of BIOS fan control and other things that I ended up sinking days into trying to solve. Right now my solution is flaky at best, but eventually the fans spin down after a reboot. Supermicro could be so good for "prosumers" but I feel like they are bogged down by historic garbage. I had to pay (crack) something in the BIOS just to use a feature.
  - c_o_n_v_e_x 4y ago
    On some server motherboards, fan control is done by the BMC. We license BMC firmware from AMI for our servers. The fan control algos that come included are very basic (similar to the proportional response the auth wrote).
- nicolaslem 4y ago
  Me too! And it does not only keep HDDs cool but even more importantly it keeps them at a constant temperature. At this point the script should be shipped with TrueNAS directly.
stefantalpalaru 4y ago
bullen 4y ago
I have spent countless hours trying to get hardware to be silent. The only way to do this reliably and without fire hazard is to passively cool the hardware completely by having HUGE heatsinks and THEN you can add a fan that you slow down with a resistor. The fan is only there to prolong the life span, the hardware should be able to run passivley at 100% and you should be able to hold your finger on the heatsink forever. If not you have a problem. All other solutions are just meaningless. http://streacom.com http://streacom.com
- mellavora 4y ago
  My son built a small project where he tried to control the speed of a computer case fan with a (variable) resistor, shunting a % of the power to ground. Didn't work very well. The fan either ran full speed or not at all. So he used a 555 chip to turn the setup into pulse-width modulation, with the variable resistor (pot) adjusting the pulse width. Worked like a charm.
  - gigaflop 4y ago
    4-wire PC fans are usually PWM controlled. That might be why the first attempt didn't go well, if he didn't try multiple fans.
- onli 4y ago
  How silent are you talking? Silent under load is hard, but quiet under load and silent on idle is possible without a passively cooled build. A good cooler for the processor + slow running case fans + a silent psu (like BitFenix Formula, Corsair RM, ...) + a noise isolating case against coil whine would be the foundation for that. I use an old Corsair H90 to cool my i5-5675C, AIO radiator is installed in the front of the case, there is one good case fan at the back. Note that the H90 is only quiet when pump speed gets also reduced. With that setup, the noise under load is completely defined by the gpu (a soon to be exchanged RX 570) and the noise of the system on idle vanishes in the ambient noise. However, the setup I describe above was loud until I got around to control the fan speeds properly. Turned out the MSI BIOS fanspeed control did not work properly. On top of high minimal speed settings (like 50% for the case fan) it ignored my cpu fan settings and ran the fans higher than I wanted. That made the system rather loud even on idle and unbearable under load. The solution was to control fanspeed with fan2go: https://github.com/markusressel/fan2go https://github.com/markusressel/fan2go (plus radeon-profile controls the speed of the gpu, making it silent on idle as well.) Fan2go is not only nice to use, it also solves the issue the article's author will run into in the future: Those hwmon paths are not stable anymore. It's possible they will work on his hardware if there is only one (or none, as in the thinkpad example using a different system), but otherwise the script will stop working with new kernels after reboots.
suprjami 4y ago
Literally the day after I spend hours figuring out thinkfan and tinkering with fan levels to get something I can live with. What timing.
suprjami 4y ago
The second solution on this page probably isn't reliable, because hwmon paths like `hwmon3` depend on module load order. That's likely the same reason for the `card*` workaround mentioned above. I am using thinkfan for this and it works really well: https://github.com/vmatare/thinkfan https://github.com/vmatare/thinkfan

51 points by hddherman 4y ago

> if ((temp > 90000)); then What is this syntax? I would have assume something like `[ $temp -gt 90000 ]` or `$((temp > 90000))`. Is the dollar here optional? Is this something bash specific?

scbrg 4y ago
> Is this something bash specific? Yes. http://mywiki.wooledge.org/ArithmeticExpression#Arithmetic_Commands http://mywiki.wooledge.org/ArithmeticExpression#Arithmetic_C...

buescher 4y ago

I was expecting a basic thermostat with hysteresis, but no, it's a stepwise proportional control. Your fan could very well wind up oscillating at one of the step transition points which is probably not great for the fan.

zbrozek 4y ago
Your sanity will suffer more than the fan.
- buescher 4y ago
  Well, there's that, but the audience is people who will write their own fan control script...
10000truths 4y ago
If this is a realistic failure mode, one would hope that there is some kind of rate-limiting at the firmware or driver level.
- buescher 4y ago
  One would hope.

mortenlarsen 4y ago

There is no need to call cat to read from a file. > temp=$(cat /sys/class/thermal/thermal_zone1/temp) temp=$(</sys/class/thermal/thermal_zone1/temp)

0xCAP 4y ago
A classic example of cat abuse in my book.
- deeblering4 4y ago
  meow
- elsyx 4y ago
  Definitely an unwarranted cat call.
piperswe 4y ago
IMO the cat version is more readable, and any performance difference should be negligible

XiS 4y ago

As an alternative, been using this PID fan control script to keep my HDDs cool for ages. https://forums.freenas.org/index.php?threads/pid-fan-controller-perl-script.50908/ https://forums.freenas.org/index.php?threads/pid-fan-control...

francis-io 4y ago
I've some a similar thing with my NAS on a Supermicro X10 (I think) on Linux. I have had all kinds of trouble getting quiet fans on this board under Linux. I think it's a mix of BIOS fan control and other things that I ended up sinking days into trying to solve. Right now my solution is flaky at best, but eventually the fans spin down after a reboot. Supermicro could be so good for "prosumers" but I feel like they are bogged down by historic garbage. I had to pay (crack) something in the BIOS just to use a feature.
- c_o_n_v_e_x 4y ago
  On some server motherboards, fan control is done by the BMC. We license BMC firmware from AMI for our servers. The fan control algos that come included are very basic (similar to the proportional response the auth wrote).
nicolaslem 4y ago
Me too! And it does not only keep HDDs cool but even more importantly it keeps them at a constant temperature. At this point the script should be shipped with TrueNAS directly.

stefantalpalaru 4y ago

bullen 4y ago

I have spent countless hours trying to get hardware to be silent. The only way to do this reliably and without fire hazard is to passively cool the hardware completely by having HUGE heatsinks and THEN you can add a fan that you slow down with a resistor. The fan is only there to prolong the life span, the hardware should be able to run passivley at 100% and you should be able to hold your finger on the heatsink forever. If not you have a problem. All other solutions are just meaningless. http://streacom.com http://streacom.com

mellavora 4y ago
My son built a small project where he tried to control the speed of a computer case fan with a (variable) resistor, shunting a % of the power to ground. Didn't work very well. The fan either ran full speed or not at all. So he used a 555 chip to turn the setup into pulse-width modulation, with the variable resistor (pot) adjusting the pulse width. Worked like a charm.
- gigaflop 4y ago
  4-wire PC fans are usually PWM controlled. That might be why the first attempt didn't go well, if he didn't try multiple fans.
onli 4y ago
How silent are you talking? Silent under load is hard, but quiet under load and silent on idle is possible without a passively cooled build. A good cooler for the processor + slow running case fans + a silent psu (like BitFenix Formula, Corsair RM, ...) + a noise isolating case against coil whine would be the foundation for that. I use an old Corsair H90 to cool my i5-5675C, AIO radiator is installed in the front of the case, there is one good case fan at the back. Note that the H90 is only quiet when pump speed gets also reduced. With that setup, the noise under load is completely defined by the gpu (a soon to be exchanged RX 570) and the noise of the system on idle vanishes in the ambient noise. However, the setup I describe above was loud until I got around to control the fan speeds properly. Turned out the MSI BIOS fanspeed control did not work properly. On top of high minimal speed settings (like 50% for the case fan) it ignored my cpu fan settings and ran the fans higher than I wanted. That made the system rather loud even on idle and unbearable under load. The solution was to control fanspeed with fan2go: https://github.com/markusressel/fan2go https://github.com/markusressel/fan2go (plus radeon-profile controls the speed of the gpu, making it silent on idle as well.) Fan2go is not only nice to use, it also solves the issue the article's author will run into in the future: Those hwmon paths are not stable anymore. It's possible they will work on his hardware if there is only one (or none, as in the thinkpad example using a different system), but otherwise the script will stop working with new kernels after reboots.

suprjami 4y ago

Literally the day after I spend hours figuring out thinkfan and tinkering with fan levels to get something I can live with. What timing.

suprjami 4y ago

The second solution on this page probably isn't reliable, because hwmon paths like `hwmon3` depend on module load order. That's likely the same reason for the `card*` workaround mentioned above. I am using thinkfan for this and it works really well: https://github.com/vmatare/thinkfan https://github.com/vmatare/thinkfan