Date: Fri, 17 Oct 2025 14:33:16 -0600 From: Warner Losh <imp@bsdimp.com> To: mike tancsa <mike@sentex.net> Cc: FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: finding cause of reboot Message-ID: <CANCZdfoJzaGhpXKjPs4H6DiLd=_CLiWq%2Bs4z1mnParN5s1JhiQ@mail.gmail.com> In-Reply-To: <00a760b4-fc94-4884-be98-167d77a08140@sentex.net> References: <aPD0ivyRrUUW-dkW@int21h> <CAOtMX2hWX63byYjKu7_EOjnDa3SvJ3PqOJLOL4cfVmxUFcP%2BYA@mail.gmail.com> <CANCZdfqN8BBr=EVE6QvHmvqofoTSqXHBBkio29ZQT-J2AJYHGg@mail.gmail.com> <569ccba4-3420-4741-925e-680fd1a1820d@sentex.net> <aPJr3YnOSdz5qC8Y@int21h> <00a760b4-fc94-4884-be98-167d77a08140@sentex.net>
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[-- Attachment #1 --]
On Fri, Oct 17, 2025, 2:12 PM mike tancsa <mike@sentex.net> wrote:
> 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
>
You can also look at the unclean shutdown count in nvme drives...
nvmecontrol logpage -p2 nvme0
to catch power issues.
Warner
---Mike
>
>
>
[-- Attachment #2 --]
<div dir="auto"><div><br><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Oct 17, 2025, 2:12 PM mike tancsa <<a href="mailto:mike@sentex.net">mike@sentex.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 10/17/2025 12:16 PM, void wrote:<br>
> On Fri, Oct 17, 2025 at 09:56:29AM -0400, mike tancsa wrote:<br>
>> Not sure if it helps in this case or not, but If you capture smartctl <br>
>> info regularly, you can some times infer from the disk power cycle <br>
>> count and power on hours if the box rebooted due to a power issue or <br>
>> not.<br>
><br>
> Good point.<br>
><br>
> I'm unsure how I'd distinguish between soft power cycle<br>
> and reboot though. The latter i'd expect to increment power cycle<br>
> count the former might but it might not.<br>
<br>
In my case, I had it with a failing power supply or one that could not <br>
deal with load. In my case showed power cycle counts increasing. Where <br>
as, a shutdown -r now before<br>
<br>
0{r-14mfitest}# smartctl -a /dev/ada0 | grep -i power<br>
entering power-saving mode.<br>
9 Power_On_Hours 0x0032 100 100 000 Old_age <br>
Always - 40206<br>
12 Power_Cycle_Count 0x0032 100 100 000 Old_age <br>
Always - 91<br>
0{r-14mfitest}#<br>
<br>
and after a reboot<br>
<br>
s0{r-14mfitest}# smartctl -a /dev/ada0 | grep -i power<br>
entering power-saving mode.<br>
9 Power_On_Hours 0x0032 100 100 000 Old_age <br>
Always - 40206<br>
12 Power_Cycle_Count 0x0032 100 100 000 Old_age <br>
Always - 91<br>
0{r-14mfitest}#<br>
<br>
At least on my SuperMicro board shows the same power cycle count. Like <br>
you said, probably does not apply in your case, but sometimes handy to <br>
keep in the back pocket<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">You can also look at the unclean shutdown count in nvme drives...</div><div dir="auto"><br></div><div dir="auto">nvmecontrol logpage -p2 nvme0</div><div dir="auto"><br></div><div dir="auto">to catch power issues.</div><div dir="auto"><br></div><div dir="auto">Warner</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote gmail_quote_container"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
---Mike<br>
<br>
<br>
</blockquote></div></div></div>
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