WD Green drives -> will provide temp via smartctl WITHOUT spinning up drive!

[bubbaQ]

I made a discovery today.....  WD Green drives will provide temp via smartctl WITHOUT spinning up drive!

 

I was writing a script to vary fan speed.... and needed to poll the CPU temp, as well as the drive temps, and act on those temps.  I first check to see if the drive is active, and if it is, check the temp.

 

Well, I had the logic backwards initially, and it checked the temp on ALL the drives, but when I refreshed the unRAID interface, the three WD green drives were still spun down.

 

So I checked each drive by hand, and sure enough, the WD Green drives return temps via smartctl when spun down.  I checked to see if it returned the CURRENT temp, or was just repeating the last temp.... I put the fans on high, to cool the drives, and the temp reported by smartctl went down without the drive spinning up.

 

FWIW, my drives are WDC_WD10EACS-00ZJB0  and WDC_WD10EACS-32ZJB0.

 

 

 

[bubbaQ]

FWIW, I am using fancontrol with lm-sensors to minimize the NOISE from my unRAID server.... but out of the box, fancontrol only monitors the cpu temps... so I was not able to vary the fans on the drive cages (those are the ones that REALLY make the noise).  Because unRAID only uses one CPU, on a dual-core system the CPU stays relatively cool with minimal CPU cooling (i.e. a QUIET fan).

 

Since the WD green drives return temps while spun down, I can put one in the center slot of each 5-drive drive cages, to act as a temperature sensor for the cage.  It ain't perfect, and I'll have to run some test.... let the drives sit spun down in the cages with the fans on the minimum speed, wait an hour, then check all the temps and see if the other drives are hotter than the WD sitting in the middle.  But at least this gives me SOME way to determine the appropriate fan speed for the fans on the drive cages.

[WeeboTech]

I made a discovery today.....  WD Green drives will provide temp via smartctl WITHOUT spinning up drive!

 

Maybe this is why my tests were working, and others were not. [me=WeeboTech]slaps head [/me]

[bubbaQ]

Finally... what I really wanted... a SILENT unRAID server.  CPU fan and PSU fan were already silent, and auto varied based on temp....but the drive cage fans were horrible.

 

I tested the drive-cage fans to find the voltage setting that is just below ambient noise, and set them to that on boot.

 

A script then checks the drive temps every minute to determine max temp of the hottest drive ... if any drive is over 35, bump up the cage fans to a speed that is audible, but not too noisy.  If any temp is over 44, crank up the fans to max.  If all the drives are spun down, I take the WD Green temps, add 2 degrees, and use those to determine the max.

 

Unfortunately, I only have one fan header that is software variable  (other than the CPU) so I have to use one header for all three cage fans.  Anyone have a suggestion for an addin card with more CONTROLLABLE fan headers?

[WeeboTech]

Anyone have a suggestion for an addin card with more CONTROLLABLE fan headers?

I remember a long time ago there used to be some fan controller card, that had a USB interface for controlling fans on the card's header.

If I remember correctly it was windows only at the time.  Maybe some searching will reveal something.

 

A script then checks the drive temps every minute to determine max temp of the hottest drive ... if any drive is over 35, bump up the cage fans to a speed that is audible, but not too noisy.  If any temp is over 44, crank up the fans to max.  If all the drives are spun down, I take the WD Green temps, add 2 degrees, and use those to determine the max.

 

COOL! 

 

Unfortunately, I only have one fan header that is software variable  (other than the CPU) so I have to use one header for all three cage fans.

 

Just a suggestion, did you check out the wattage of the fans to make sure they do not exceed the motherboard fan header power specs?

[bubbaQ]

I remember a long time ago there used to be some fan controller card, that had a USB interface for controlling fans on the card's header.

If I remember correctly it was windows only at the time.  Maybe some searching will reveal something.

 

It was from Sunbeam... and the software SUCKED badly.... and never came out with a Linux version.

 

Just a suggestion, did you check out the wattage of the fans to make sure they do not exceed the motherboard fan header power specs?

 

Yup.... all together they draw a measured 12 Watts, which is w/in spec.

[Joe L.]

Unfortunately, I only have one fan header that is software variable 

What linux command is used to change the voltage/speed of the software controlled fan header? 

 

Joe L.

[bubbaQ]

You just write the pmw value out to the proper device under the /sys/class/hwmon/ hierarchy.... depends on what sensor chips you have.