Ian Kelling posted on Thu, 26 Nov 2015 21:14:57 -0800 as excerpted: > I'd like to run "mail" when a btrfs raid drive fails, but I don't know > how to detect that a drive has failed. It don't see it in any docs. > Otherwise I assume I would never know until enough drives fail that the > filesystem stops working, and I'd like to know before that. Btrfs isn't yet mature enough to have a device failure notifier daemon, like for instance mdadm does. There's a patch set going around that adds global spares, so btrfs can detect the problem and grab a spare, but it's only a rather simplistic initial implementation designed to provide the framework for more fancy stuff later, and that's about it in terms of anything close, so far. What generally happens now, however, is that the btrfs will note failures attempting to write the device and start queuing up writes. If the device reappears fast enough, btrfs will flush the queue and be back to normal. Otherwise, you pretty much need to reboot and mount degraded, then add a device and rebalance. (btrfs device delete missing broke some versions ago and just got fixed by the latest btrfs-progs-4.3.1, IIRC.) As for alerts, you'd see the pile of accumulating write errors in the kernel log. Presumably you can write up a script that can alert on that and mail you the log or whatever, but I don't believe there's anything official or close to it, yet. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
