On Tue, Jun 24, 2014 at 4:02 PM, Alan McKinnon <[email protected]> wrote: > > External drives have a much higher failure rate than internal drives. > people don't expect them to fail or be dropped or accidentally plugged > in in the wrong order and the wrong one to be mkfs'ed (until it does > happen). These are real risks that you can't ignore whereas with a good > internal drive you can often get away with it. >
++ Don't ignore the potential for logical errors. If you have some script that magically rsyncs stuff then don't make the mistake of moving data over and rsyncing the old copy over the new, or mounting the devices in a manner that isn't robust when udev changes all your device labels, and so on. That seems like the most likely way your data is going to get scrambled, unless you have them both in your car and end up in a crash. That was one of the reasons I went with btrfs for my offline copy. If it unmounts, then I know I have two copies of everything. If it mounts, I know it found both mirrors. If I scrub and there are no errors, then I know both copies are good. You can do that in other ways, but make sure you actually catch the failure modes. Rich
