Linux force reboot/shutdown

Forcing reboot

Linux is not Windows XP and if reboot fail you usually still connect by SSH and do something. This commands will show you how to remotely hard reboot machine. Hard reboot mean that shutdown scripts will not run and machine reboot immediately without syncing hard disk drives, shutdown applications etc, it’s more like hitting the reset button.

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

This commands enable sysrq and after this calls fast reboot. If you want to force shutdown machine try this.

Force shutdown

echo 1 > /proc/sys/kernel/sysrq
echo o > /proc/sysrq-trigger

Pasted from <http://blog.air4web.com/linux-force-reboot.html>
This came handy, when I had a server that had some IO error and it can no longer read from disk, only few cached binaries into memory kept it running (kernel, SSHD, bash), I could still access the machine via SSH but can no longer do anything, forcing the reboot as mentioned above was my only resort, and it worked like charm…
http://smshaker.wordpress.com/2009/03/02/linux-force-rebootshutdown/