/proc/sys/kernel/sysrq if it exists and contains the value 1, all possible requests are allowed.
Press Alt-Sysreq, then one of the following letters:
|r||Unraw: Restores the keyboard after an X crash or similar.|
|0||Changes console loglevel to 0 and so reduces error messages.|
|k||System attention key: Kills all processes on the current virtual console.|
|e||Terminate: Kills all processes except init on the current terminal.|
|i||Kill: Kills all processes except init, everywhere.|
|s||Sync: Attempts to sync all mounted filesystems. Outputs OK and Done when it's managed. This can reduce the chances of needing to run fsck at a later stage so it can be useful if you're having disk problems.|
|u||Umount: Attempts to remount all mounted filesystems read-only.|
|b||Reboot: immediately reboots the system without syncing or unmounting disks. Not a good idea unless in extremis! This may lead to data loss.|
|p||Dumps current registers and flags to the console.|
|m||Dumps current memory info to the console.|
If this doesn't work, check the documentation at /usr/share/doc/linux-doc-2.6.18/Documentation/sysrq.txt.gz for some suggestions (including checking the keycode being sent).
This article was first published on ServerWatch.com.
One of the ways around the issues of security and control that make some businesses wary of cloud computing is to build a private cloud -- one that remains within the corporate firewall and is wholly controlled internally. Private clouds also increase the agility of IT an organization's IT infrastructure and make it easier to roll out new technology projects. Download this eBook to get the facts behind the private cloud and learn how your organization can get started.