Last night, my UPS started beeping in the middle of the night. This happened once before recently, and that time I just pushed the button on the front to see if it would reset the problem, but it turned the power completely off. That time, after my linux box booted, the two external USB backup drives came up really slow, which caused the hourly rsync backups to take more than an hour, which caused all sorts of hilarity. So this time I decided to shut everything down gracefully before I reset. And yet, this morning I got up to find that four hourly backups are still running.
I killed all the backups, unmounted the usb drives, ran fsck (which didn’t do anything because it said they were clean), powered them off, powered them on, made sure it said they were “high speed” rather than “full speed”, and mounted them. And yet when I did an ls on each one, it hung for over a minute, and then had a message in the log about resetting the USB controller, and then it was fine. I’ve started an hourly backup, and it’s taken 15 minutes or more already and it’s still on the first drive. That’s not good. I wish I knew what was going wrong there.
My first order of business is probably to order new batteries for the UPS. Each time it starts beeping in the middle of the night, munin tells me that the “charge percent” has stayed at 100%, but the runtime in minutes has dropped to zero. Very odd.
Whenever I’ve seen an external USB harddrive do what you described it was the power supply to the drive going bad; replacing the power supply solved the problem. I’m thinking the cases I got weren’t designed for 24×7 operation!