Xserve G5 keeps shutting down

[Paul Mather]

On Jun 29, 2011, at 4:20 PM, Nathan Whitehorn wrote:

> On 06/29/11 15:11, Paul Mather wrote:
>> On Jun 29, 2011, at 11:25 AM, Paul Mather wrote:
>> 
>>> On Jun 27, 2011, at 10:41 AM, Nathan Whitehorn wrote:
>>> 
>>>> On 06/27/11 09:28, Paul Mather wrote:
>>>>> On Jun 25, 2011, at 8:52 PM, Nathan Whitehorn wrote:
>>> 
>>>>> What is odd, to me,  is that this power-off occurred even
>>>>> after commenting out the shutdown line in the thermal power
>>>>> management driver.  So, it must be something else that is
>>>>> forcibly powering off the system, maybe something in
>>>>> OpenFirmware, rather like some PC BIOSes will initiate a
>>>>> power-off when temperatures exceed critical. But, what is
>>>>> definitely odd is that temperatures don't seem to get so high
>>>>> as to be critical, so perhaps it is some other hardware state
>>>>> that is triggering the power-off?
>>>> 
>>>> Yes, something like that seems likely, either some strange
>>>> firmware thing or the PMU microcontroller becoming unhappy. A few
>>>> more things to try: 1) Does setting machdep.manage_fans=0 from
>>>> the loader change anything?
>>> 
>>> I am trying that now.
>> 
>> 
>> Just to follow up myself, I can report that I tried that and it
>> eventually powered off the machine uncleanly, too, so no ultimate
>> change in outcomes there. :-(
>> 
>> I'm beginning to wonder if this has anything to do with the fans or
>> the temperature.  Tomorrow I'll power on the system and let it run
>> idle and see if it still powers off.
>> 
>> Do you think it would be worthwhile resetting the PMU?
> 
> That's unfortunate. Can you go through SVN history and make sure that the revision before the thermal control code worked?


I've done some more troubleshooting, having become more convinced that this is probably not fan/thermal-related.  The system would power off even when the system was idle and the fans/temperature weren't being pushed.  Furthermore, I installed Mac OS X 10.5 on an external FireWire drive and booted from that with the same result: the Xserve G5 will power off after a while.

In the Mac OS X logs I would see this line upon a subsequent reboot: "ApplePMU::PMU forced shutdown, cause = -122".  An Apple Support article (http://support.apple.com/kb/TS2109) states "The -122 shutdown value indicates that the computer shutdown as the result of a power-related issue."  It goes on to suggest:

"Typically, the -122 entry is present if an Xserve experiences a complete power loss or a fluctuation in power supply that requires the Xserve the shut down. If your Xserve shuts down as a result of a power-related issue, it is recommended that you investigate the power source for reliability."  The Xserve is plugged into a UPS right now, and other equipment plugged into that UPS shows no power-related issues.  (I also plugged the Xserve directly into the wall socket but still get the power-off behaviour.)

The followup suggestion in the support article is to "use Xserve Remote Diagnostics to inspect your Xserve G5."  I've already done that, and the Xserve passed all tests.  The final support article suggestion---"If your Xserve continues to shutdown or reboot automatically as the result of power-related issues, (value -122) please contact AppleCare"---is not viable, given we have had this Xserve many years and any AppleCare will have expired by now.  (They were bought on grant money, so you know how that goes.)

So, unless anyone has any other suggestions to fix this, it looks like a bad/dying power supply is to blame for this issue.  Sorry for the false alarm!

Cheers,

Paul.