Unknown restart, where are logs

[toolshed]

If a machine goes down for an unknown restart. Where would all logs be that would help be fine out the reason of the restart.

I was currently away when the restart happen. I do know this, it was not a power failure. I know that for sure.

Log I know about.
/var/log/messages

[Daedrus]

Did the system got through a restart procedure (ie shutdown of services and restart) or did it react like you hit the reset button?

[toolshed]

I am not sure if there was a restart procedure or not. That is one of the reason I am looking for some logs to help me figure out what happen.

I am afraid that there was not a restart procedure, thus probably no logs will have been written to.

All I know is that the the power did not go out and machine was restarted.

[Daedrus]

First, it is possible that a hardware problem in the system could cause a spiratic reboot and no logs would show anything.

Second, check through your /var/log/messages file for a syslogd restart (cat /var/log/messages |grep restart) Look for the last one and see if it coincides with the reboot you were speaking of or a reboot that you did yourself. I think that this shows up in messages when a restart command is given, not when the system comes back up, but I might be wrong.

[toolshed]

yea I see an entry of syslogd restart at the time. However there is no mention of a user/system intiated restart.

I am trying to find the reason of the restart...kernel panic or hardware failure. looks like nothing was written to any logs.

kernal panics and hardware issues are written to /var/log/messages, correct?

[Daedrus]

Kernel panics will be logged in /var/log/messages. try grepping for them. Hardware problems won't necessarily show up in a log. PSU failures would reboot the system without giving it time to write a log.

[toolshed]

What do mean PSU failures would reboot system?
PSU runs out of juice?

[Daedrus]

No, faulty PSU can cut power to the system with not other signs other than the system rebooting. Power fluctuations in the power supply can cause reboots.

I did some testing and the entry syslogd: restart shows up when the system comes up again. i will continue to look for some more answers for you.

try grepping messages for "init: Switching to runlevel: 6"
when a reboot is commanded, this would show up a little before the syslogd: restart entry. If it isn't there, it was most likely a hard reboot (hardware caused).

[toolshed]

Yea, that is what I am thinking. Something kicked it off, no kernel panics were registered and no logs....looks like it just kicked off and came on.


Just got back from vacation, will ask roomates if they noticed anything..like power going on. They said nope.

Might have to call scooby on this one.

[Daedrus]

Unless it happens again, I wouldn't worry about it.