Sun SPARC T1000 - noisy fans

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TRACKER

Active Member
Jan 14, 2019
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Hello STH folks,

recently i've bought old Sun SPARC T1000 server, which i plan to use from time to time to play with :)
However, fan noise is just unbearable. All 4 fans are spinning at almost 10k rpm, even though total server consumption is 150-180W.
Even after Solaris 10 has completely booted, rpms don't decrease (even a little bit)
I tried to find more info on internet how to / can rpms be decreased, but no luck.
I've already updated ALOM/PROM firmware to latest available (server is out of support for almost 10 years already).
Output from prtdiag is attached.

If anyone has any ideas or suggestions, would be really appreciated!
 

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sko

Active Member
Jun 11, 2021
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121
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Those were pure-bred datacenter servers, noise was completely irrelevant.
The fans are temperature controlled, but even on lowest settings they are quite loud.

You can replace the fans with some lower-rpm ones. IIRC the minimum threshold is somewhere around ~6000rpm for the system fans. They will throttle to lower rpms, but they must spin above that threshold during startup.
For the PSU the threshold is much higher (>10k rpm), and the ALOM will shut down the system if the threshold is undershot. There's only an "OK/FAIL" value for the PSU fans, so I tested that with a function generator (and a lot of cold boots, because the FAIL status won't be reset by the initial system check).
I've used a simple adjustable frequency generator (a few bucks on aliexpress) to fake the rpm signal with a 30kHz GND signal. Minimum threshold is somewhere around 24kHz. (IIRC this corresponds to 12k rpm)

I've replaced the Fans in my T1000 with Sunon MB40201V1 (7200rmp, 0.84W, 0.25m^3/min). They will run at ~4500-5000rpm under normal load, except the PSU fan which always runs at full speed and it definitely has to as the PSU gets quite warm/hot! It never triggered the overtemp, but still it's really at the edge of my personal comfort zone - it gets too hot to touch if the system gets some load.
With those Sunon fans the system is much quieter and bearable, but still, this is a 1U server and was never designed to be quiet. So there's no chance in hell you will get that system quiet enough to be running unnoticed in your living room. There's still a very notable airflow noise and I wouldn't try to go lower with the fans. As said - the PSU already gets relatively hot despite the room being air conditioned to ~22°C.
And no - noctua fan's won't work. They are only quiet because they don't move any air as soon as there is the tiniest bit of backpressure, and you *will* need fans that can build up some static pressure in a 1U system.



Here's the 'showenv' output after a few minutes of uptime (running OpenBSD in primary LDOM and in 2 LDOMs as redundant firewalls)

Code:
=============== Environmental Status ===============


--------------------------------------------------------------------------------
System Temperatures (Temperatures in Celsius):
--------------------------------------------------------------------------------
Sensor           Status  Temp LowHard LowSoft LowWarn HighWarn HighSoft HighHard
--------------------------------------------------------------------------------
MB/T_AMB         OK        31    -10      -5       0      45       50       55
MB/CMP0/T_TCORE  OK        49    -10      -5       0      85       90       95
MB/CMP0/T_BCORE  OK        49    -10      -5       0      85       90       95
MB/IOB/T_CORE    OK        55    -10      -5       0      95      100      105

--------------------------------------------------------
System Indicator Status:
--------------------------------------------------------
SYS/LOCATE           SYS/SERVICE          SYS/ACT            
OFF                  OFF                  ON                 
--------------------------------------------------------

----------------------------------------------------------
Fans (Speeds Revolution Per Minute):
----------------------------------------------------------
Sensor           Status           Speed   Warn    Low
----------------------------------------------------------
FT0/F0           OK                4435   2240   1920
FT0/F1           OK                4342   2240   1920
FT0/F2           OK                4483   2240   1920
FT0/F3           OK                4296   2240   1920

--------------------------------------------------------------------------------
Voltage sensors (in Volts):
--------------------------------------------------------------------------------
Sensor          Status      Voltage LowSoft LowWarn HighWarn HighSoft
--------------------------------------------------------------------------------
MB/V_VCORE      OK            1.31    1.20    1.24    1.36     1.39
MB/V_VMEM       OK            1.79    1.69    1.72    1.87     1.90
MB/V_VTT        OK            0.87    0.84    0.86    0.93     0.95
MB/V_+1V2       OK            1.18    1.09    1.11    1.28     1.30
MB/V_+1V5       OK            1.48    1.36    1.39    1.60     1.63
MB/V_+2V5       OK            2.47    2.27    2.32    2.67     2.72
MB/V_+3V3       OK            3.27    3.06    3.10    3.49     3.53
MB/V_+5V        OK            4.99    4.55    4.65    5.35     5.45
MB/V_+12V       OK           12.25   10.92   11.16   12.84    13.08
MB/V_+3V3STBY   OK            3.29    3.16    3.23    3.43     3.49

-----------------------------------------------------------
System Load (in amps):
-----------------------------------------------------------
Sensor           Status              Load     Warn Shutdown
-----------------------------------------------------------
MB/I_VCORE       OK                20.560   80.000   88.000
MB/I_VMEM        OK                 5.820   60.000   66.000
-----------------------------------------------------------


----------------------
Current sensors:
----------------------
Sensor          Status
----------------------
MB/BAT/V_BAT     OK


------------------------------------------------------------------------------
Power Supplies:
------------------------------------------------------------------------------
Supply  Status          Underspeed  Overtemp  Overvolt  Undervolt  Overcurrent
------------------------------------------------------------------------------
PS0     OK              OFF         OFF       OFF       OFF        OFF
 

TRACKER

Active Member
Jan 14, 2019
169
48
28
Hello sko,

thanks a lot for the detailed explanation.
I fully agree with you, that this server would never be so quiet to run unnoticed. That is not my goal anyway :)
I already have some equipment in my home lab, running 24/7 and small amount of noise is ok, but T1000's noise is just beyond any reasonable levels.
So the only way is to replace the fans and to use adjustable frequency generator.
~4500-5000rpm sounds much more bearable.
I will see what i can do with fans replacement. Regarding the frequency generator, that would be harder for me, i never dealt with that type of electronics :)
Anyway, thanks again for the directions!
 

sko

Active Member
Jun 11, 2021
227
121
43
Then you should be fine with the noise level of those Sunons. In my homelab the T1000 doesn't drown out the stack of 2x cisco 3750X and my main server (supermicro 6028U-TR4T+), but is at about the same level. The relatively thick metal on those Suns prevents the kind of body noise you get with newer servers, but the airflow is very noticeable.


Regarding the frequency generator, that would be harder for me, i never dealt with that type of electronics :)
Just search for "NE555 frequency generator" or "square wave signal generator" - the only thing you have to consider is the frequency range (>24kHz). Those simple circuits usually support 5-12V input and the default is a pulsed GND signal, so this matches exactly what you need to mimic a fan RPM signal. Those circuits have 3 pins - Vcc, GND and Signal out - so absolutely no rocket science.
The simple ones for ~0.30-0.50EUR/$ are perfectly fine, but you could also use one of the variants with a display and buttons to adjust the frequency (e.g. https://www.aliexpress.com/item/1005005426933065.html)
Fans are rather bad signal generators, so the inputs are usually very forgiving when it comes to dirty/wrong waveforms (e.g. sine wave) or wrong duty cycle (~50%), but those NE555 are more than sufficient.

Keep in mind that you have to open the PSU to change the fan and re-route the signal line to wherever you want to put the frequency generator (I attached it to the wiring loom with a cable tie). So the usual warnings about unplugging mains, insulating everyting properly etc pp apply here - if in doubt ask someone who is experienced with working on electronics.
 
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