On Tue, Jun 08, 2004 at 11:25:55AM +0200, Markus Hitter scratched on the wall:

Am 08.06.2004 um 06:56 schrieb Jay A. Kreibich:

...

So my thought is to modify the UPS scripts to "almost" shut the

...

machine down, and then just let the power fail.

If my iBook's battery goes low it does a force sleep. Even with almost

empty batteries, the state of the machine can be hold for more than a

day until it goes off completely. If you force sleep with a full UPS,

sleeping the machine for several weeks shouldn't be a problem.

You're assuming the machine is the only thing plugged into the UPS. It isn't. There's some networking gear and monitoring hardware also connected. If we put the server to sleep (interesting idea!) that would only buy 30 to 40 minutes. I suppose we could get a second UPS for just the computer, but that seems excessive. The need to go this long is rare, so we're OK with the machine going down. I just want it to come back without having to press the power button. Regardless, there's also an issue with how to wake the machine back up. Wake-on-LAN might work, but you would need to actively monitor the situation and send packets, but not before you're sure the UPS has recovered. That's messy and tricky. Also, if we're in a situation where the power is likely to have failed (e.g. thunderstorm) the networking out there is less than ideal, and is likely to have been effected. That's part of the reason for the machine out there-- it can spool data and deliver it when we've got a good connection. Believe me, I know this situation is far from ideal, but it works well enough. I just wanted to try to cover all our bases with the UPS. There have been times when the system was down longer waiting for someone to drive out there and press the power button than it was out because of loss of power.

Unless the Power Manager is buggy, he should do all the syncing for you.

I wouldn't assume the sleep flushes the file system. I suppose it wouldn't be a bad idea for the force-sleep, but the it would slow down the standard sleep quite a bit. Besides, that's only half the issue. The software we have will correctly deal with a SIGHUP to shut itself down gracefully, but would be unhappy to go to sleep and then (maybe) loose power. Putting the machine to sleep changes the game a bit, but you still have the risk of loosing power. -j -- Jay A. Kreibich | Integration & Software Eng. jak@uiuc.edu | Campus IT & Edu. Svcs. <http://www.uiuc.edu/~jak> | University of Illinois at U/C _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.