One morning last week I woke up to find the LED on my NAS a solid red. I've never been happier to have something fail.
I'd set up my backup jobs to fire off a systemd unit on failure
This is a generator-service, which is used to fire off an email to me when something goes wrong. I followed these instructions on the Arch wiki to set it up. Once I got the blinkstick, I added an additional command to that service to light up the LED:
ExecStart=-/usr/local/bin/blinkstick --index 1 --limit 50 --set-color red
The actual failure was a simple thing to fix. But I never did get the email.
On further investigation, there are problems with using
Debian at the moment: it's possible for the
exim4 daemon to exit and for
systemd not to know that this is a failure, thus, the mail spool never gets
processed. This should probably be fixed by the
exim4 package providing a
systemd service unit.