Justin wrote: > Howdy Matt. Just to make it absolutely clear, I appreciate your > response. I would be quite lost if it weren't for all of the input. > >> Unplugging a drive (actually pulling the cable out) does not >> simulate a drive failure, it simulates a drive getting unplugged, >> which is something the hardware is not capable of dealing with. >> >> If your drive were to suffer something more realistic, along the >> lines of how you would normally expect a drive to die, then the >> system should cope with it a whole lot better. > > Hmmm... I see what you're saying. But, ok, let me play devil's > advocate. What about the times when a drive fails in a way the system > didn't expect? What you said was right - most of the time, when a > hard drive goes bad, SMART will pick up on it's impending doom long > before it's too late - but what about the times when the cause of the > problem is larger or more abrupt than that (like tin whiskers causing > shorts, or a server room technician yanking the wrong drive)?
I read a research paper by google about this a while ago. Their conclusion was that SMART is poor predictor of disk failure, even though they did find some useful indications. google for "google disk failure", it came out as second link a moment ago, title "Failure Trends in a Large Disk Drive Population". The problem with trying to predict disk failures with SMART parameters only catches a certain percentage of failing disks, and that percentage is not all that great. Many disks will still decide to fail catastrophically, most often early morning December 25th, in particular if there is a huge snowstorm going :) Heikki _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
