Start with /var/log/syslog and /var/log/dmesg current and previous
versions, depending on which has the date/time range you're looking
for.
If you automatically download and install [any/all] updates, then there
are other /var/log/ files you'll need to correlate.
It wouldn't hurt to also look at /var/log/ufw.logs to see if anything
reported by your firewall would correlate to the date/time of the
issue.
You may not find anything that is actionable in those logs to identify
the culprit, but you might. Do you have any external telemetry logging
that you could also correlate?
If it's a power supply failing or some component overheating, you are
unlikely to be able to find that in any standard logfile.
Good luck with your forensics.
On Sun, 2018-06-03 at 14:47 -0500, o1bigtenor wrote:
> Greetings
> 
> I am quite new at running a server so hopefully the question isn't
> too
> out there.
> 
> My server has been operational for about a year and I am working on a
> number of different projects on it. Twice now (this last friday and 5
> weeks early I came into the office to find that the server has
> somehow
> been taken down and  has rebooted itself (process setup in the bios)
> but as it doesn't quite complete the boot process, I have to hit a
> key
> to tell it to continue and then finally to log in to read Debian
> (stable).
> 
> So I am trying to determine what may have caused the system to do a
> reboot, whilst I have my suspicions I want to figure out exactly what
> is happening to cause this kind of behavior. AIUI servers should be
> able to run happily for years without issues (barring hardware
> problems) so I want that kind of reliability. Where in /var/log will
> I
> be finding the most clues as to the events that lead up to this
> 'reboot'?
> 
> Thanks in advance!!
> 
> Dee
> _______________________________________________
> TCLUG Mailing List - Minneapolis/St. Paul, Minnesota
> tclug-list at mn-linux.org
> http://mailman.mn-linux.org/mailman/listinfo/tclug-list
> 
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