[BBLISA] MBR that reboots machine

[Edward Ned Harvey (bblisa4)]

> From: bblisa [mailto:bblisa-bounces at bblisa.org] On Behalf Of Alex Aminoff
> 
> We have also thought of using a USB stick,
> but those are unreliable and we would have to buy and configure 20-30
> USB sticks.

I have actually deployed USB sticks as permanently connected boot devices to servers in a remote colo before. My experience is: They are only unreliable if you expect the system to actually use them continuously. In other words, don't try to run your server OS from them, but go ahead and leave them connected as boot devices that are configured to automatically reboot. That works fine.

I have also worked in quality assurance and qualification, where we stress tested and otherwise tested things that people don't normally test. My experience is that a *continuous* reboot loop will cause most systems to fail at some point. Simply, during each reboot, there's a small percent chance that BIOS gets hung or something like that, requiring a power cycle. Continuous rebooting is not something that manufacturers regularly design or test for. So my advice is to put a sleep statement in there. My gut feel says 5 minutes is probably a healthy compromise between getting the systems back up quickly enough that you don't have to drive to the colo or wake the on-duty, yet probably will get most of the systems back up again.

I did not do *exactly* what you're trying to do. I did not have USB sticks permanently attached, in a reboot loop. I did have servers attempting to use N-way usb redundant devices as OS boot drives. Using them as OS drives, system reliability was garbage, but every time the colo guy power cycled the servers (many times, before we were able to replace all that mess) reboots were always reliable.

Using "dd" to create 20 USB drives, I think, will not cost you much time or money.

If you find your rebooting MBR, that's probably best. Otherwise, don't outrule the USB solution.