Re: finding cause of reboot

On 10/17/2025 12:16 PM, void wrote:
> On Fri, Oct 17, 2025 at 09:56:29AM -0400, mike tancsa wrote:
>> Not sure if it helps in this case or not, but If you capture smartctl 
>> info regularly, you can some times infer from the disk power cycle 
>> count and power on hours if the box rebooted due to a power issue or 
>> not.
>
> Good point.
>
> I'm unsure how I'd distinguish between soft power cycle
> and reboot though. The latter i'd expect to increment power cycle
> count the former might but it might not.

In my case, I had it with a failing power supply or one that could not 
deal with load.  In my case showed power cycle counts increasing.  Where 
as, a shutdown -r now before

0{r-14mfitest}# smartctl -a /dev/ada0 | grep -i power
                                         entering power-saving mode.
   9 Power_On_Hours          0x0032   100   100   000    Old_age 
  Always       -       40206
  12 Power_Cycle_Count       0x0032   100   100   000    Old_age 
  Always       -       91
0{r-14mfitest}#

and after a reboot

s0{r-14mfitest}# smartctl -a /dev/ada0 | grep -i power
                                         entering power-saving mode.
   9 Power_On_Hours          0x0032   100   100   000    Old_age 
  Always       -       40206
  12 Power_Cycle_Count       0x0032   100   100   000    Old_age 
  Always       -       91
0{r-14mfitest}#

At least on my SuperMicro board shows the same power cycle count.   Like 
you said, probably does not apply in your case, but sometimes handy to 
keep in the back pocket


     ---Mike