One of my centos host rebooted recently unfortunately no monitoring was implemented .
How can i find out what caused it to reboot. i only have ssh access to it.
How can determine if the cause is due to Following:
1.power failure.(Will there be any special non maskable interrupt logged some where) 2.Intentional hard reset.(will it be possible to differentiate between power failure n reset also what will be Signal to look for?). 3.manual reboot command(How to differentiate this from hard reset,will inode reveal anythng related to this like "**Cleaning Orphaned node**" any special signals?) 4.Low disk space.(there is no message in /log/messages 30 minutes before restart,something stopped daemon from writing to log, disk space was ok ). 5.Overloaded CPU (Not configured to run any cronjob for saving sar o/p,Currently load average is normal Will there be any special signal to look for when CPU is loaded.) 6.Low RAM(currently there is more than 24 GB free space
I am interested in knowing the difference between intentional(hard reset/command issued) and power failure reboot.