On Tue, 2012-08-07 at 23:18 -0500, Dale wrote: > William Kenworthy wrote: > > On Tue, 2012-08-07 at 21:19 -0500, Dale wrote: > >> Paul Hartman wrote: > >>> On Tue, Aug 7, 2012 at 5:26 PM, Dale <rdalek1...@gmail.com> wrote: ... > > Goggle have a well known document > > (http://research.google.com/archive/disk_failures.pdf) where they > > analysed hard drive failures for a very large number of drives ... the > > basic upshot is that a very large portion of failures happen with no > > pre-warning, so testing a drive like you are proposing not going to > > prove a thing. > > > > They also found that smart (is quite dumb) and its tests were of little > > use. > > > > And high temperatures and work loads were also not a reliable guide to > > trends in failure rates, both of which which surprised me. > > > > Some of those bathtub curves that I was trained on when setting > > maintenance schedules dont hold water here! > > > > This anaysis of the paper looks quite good if you want the lite view: > > http://storagemojo.com/2007/02/19/googles-disk-failure-experience/ > > > > BillK > > > > > > Well, I am going by actual real experiences from other users of this > model of drive. I don't know what google was testing but I would bet it > is not the drive model I just bought. The users who bought this exact > model drive report that most failures are either out of the box or > within a few weeks to a month. I'm just going to try to increase my > odds even if it is just a little bit. > > Smart may not always predict a failure but it is better than nothing at > all. Would you rather have a tool that may predict a failure or no tool > at all? Me, I'd rather have something that at least tries too. The one > drive I had to go bad, Smart predicted it very well. It said I had > about 24 hrs to get my stuff off. Sure enough, the next day, it > wouldn't do anything but spin. Without Smart and its prediction, I'd > have lost the data on the drive with no warning at all. > > A couple questions. What if while I am testing this drive, it dies? > Does that prove that my testing benefited me then? > > Dale > > :-) :-) >
Read the paper - its written by someone who buys drives in batches of 100's+, not by a few guys posting on a forum somewhere who bought one random drive, who probably didn't use anti-static techniques handling the drive, and thumped it around in the boot of the car or got it via the courier who was famous for delivering TV's by throwing them over the fence. It is a bit of an eye opener - read it. My impression of models is that it is not really the model that has a run of failures, but the batch so a different run of the same model will have a different failure pattern. There are exceptions such as those IBM 60G deathstar drives, but then again they fixed it and following drives of the same model were fine. My own experience of smart is it tells you something, but what it seems to say is not right (notice I am not saying it tells lies, but that the data and interpretation don't make sense on the drives Ive had) Drive failure does seem to be a semi-random lottery, but I am seriously doubtful that testing will do anything ... it has as much chance of precipitating failure that wouldn't occur otherwise because you are seriously hammering it, or weakening the drive so it will fail at some random time, but perhaps weeks away rather than the years it otherwise would, or nothing will happen except for wasted electrons. Then again, I am of the view that modern electronics is designed/programmed to fail a few seconds past warranty expiry (why else do most devices have timekeeping built in :) BillK
