powerswitch by com port

Question

I would like to be able to reboot a server which is prone to go into a "hard lock" (ie I am even unable to reset it with "magic sysrq", neither see anything on screen nor get nothing out of the logs afterwards).

I wondered about connecting a cord from another computers com port and "break the power" with a fancy command from shell. The big problem is: I know next to nothing about com ports and how they send out interference...

Does this product exist? Do anybody know of how to create one in the office?

Answer 1

There are a variety of RS-232 / serial controller power switches out there. I'll include links to a couple products below. They are not inexpensive, typically.

Some UPSs have switchable output groups and to allow you to power-cycle outlets on the UPS via its management interface. Be sure to look into that.

If your server computer has a "lights out" management interface (HP/Compaq iLO, Dell Remote Assisance Card) you can typically power-cycle the host system from that management interface as well.

• http://www.startech.com/item/PCM815SHNA-8-Outlet-Remote-Power-Switch-RS232-Interface.aspx

• http://www.wti.com/power-reboot-switches.html

Finally, here's a how-to "do it yourself" article, but I'd highly recommend against doing anything like this for a serious datacenter environment.

• http://www.streettech.com/modules.php?op=modload&name=News&file=article&thold=-1&mode=flat&order=0&sid=1504

Answer 2

If it's true server-grade hardware (not a re-purposed desktop) it will likely have built-in IPMI controls. For example, my Penguin Computing and Dell servers can all be rebooted or powered on/off remotely regardless of the state of the OS.