Google published a study on disk failures. http://research.google.com/pubs/pub32774.html
They provide some interesting data on AFR as a function of disk age among other data Deepak On Apr 19, 2013, at 2:50, Fred Youhanaie <[email protected]> wrote: > > > On 19/04/13 00:01, mathog wrote: >> High end SATA and SAS disks claim MTBF values that work out to over 100 >> years, and yet it is a common >> observation that certain models fail at rates entirely inconsistent >> with those values. For instance, >> 75% of all drives of one model dead in < 6 years. (Cited by one poster >> in this thread: >> >> https://groups.google.com/forum/#!topic/comp.unix.solaris/zQjoyc8T01Y >> >> ). Additionally, manufacturer warranties at best only go to 5 years, >> which suggests the manufacturers >> don't have a whole lot of faith in their MTBF values. >> >> Some of you have huge amounts of storage, how many disk models lasted >> as long as their MTBF suggests >> they should? (Personally we have only one set of disks that are still >> consistent with the claimed MTBF, >> a set of 6 Fibre Channel disks that came with a Sun server and are now >> 10 years old - with no failures.) > > You may find this paper helpful, some of the data sets used in their studies > come from large HPC sites: > > Bianca Schroeder, Garth A. Gibson > Understanding disk failure rates: What does an MTTF of 1,000,000 hours > mean to you? > http://dl.acm.org/citation.cfm?doid=1288783.1288785 > > If you, or your institution, do not have access to the ACM publications, you > may be able to find a free copy posted by the authors, ACM does allow that :) > >> How do they come up with the MTBF values for disks anyway? Clearly it >> is not based on watching a large >> sample of disks for countless years! > > I can't remember if I have read it in the above paper or elsewhere that users > in the field tend to replace disks on the first signs of failure, e.g. SCSI > warnings, while manufacturers' tests may run > to total failure, which leads to claims of longer MTTF/MTBF values by the > manufacturers. > > Cheers > Fred > _______________________________________________ > Beowulf mailing list, [email protected] sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf
_______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
