UPS annoyances

My NAS is plugged into my APC 550 UPS. The UPS's USB status cable is plugged into the NAS, so it gets notified of status changes.

No power outages have occurred, but occasionally the NAS will shut itself down. I've figured out why.

The UPS reports minor power outages (such as a spike when the printer warms up) like this:

16:15:18 Power loss detected.
16:15:24 Power has returned.

The NAS shut itself down this morning. This is what the log says:

11:07:41 Power has returned.
11:07:42 Power loss detected.

That's right! The message cancelling the shutdown arrives one second before the shutdown message. The NAS dutifully cancels a non-existent shutdown, then goes right ahead and starts its shutdown timer.

This is really dumb. My Mac can read the UPS battery status (allowing behavior like “shut down when UPS battery level is critical”) and the power status, rather than relying on this erroneous transition model. Why can't my Linux-based NAS?

Posted at 2008-03-23 11:34:32 by Richard • Link to UPS annoyances
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