On Sun, Jul 3, 2011 at 11:49 AM, Dave <[email protected]> wrote: > To some extent my experience with hard drives has been random also, > however I distinguish two types of drive failures. > > 1. A "soft" failure where the drive simply starts having more and more > bad sectors and has to be replaced. > 2. A serious failure "lights out" failure where all data is suddenly > unavailable. > > Without a doubt, I have had many more WD drives go from being ok one > day to unavailable the next day than Seagate drives. > > I think that Seagate drives tend to fail softly while WDs simply go > belly up. "I" (myself and my customers) have had multiple WD drive > failures like this in the past two years.
Well, I always blamed this on progress in the art of disk diagnostics. There is a substantial layer of error detection and correction in the firmware of every drive on the market since mid 90s, called SMART. It was an IBM invention, but it got included in the ATA spec so that everybody else had to implement it, too. SMART looks for errors in the functioning of the drive, and corrects correctable errors, and replaces sectors that consistently go bad. It even keeps statistics on the ongoing drive health, so if you are looking at SMART data, you can sometimes (or maybe even often?) anticipate the drive going bad, but you'd have to either do it manually (smartctl or skdump) or automatically (smartd). If one does NOT pay attention to SMART, the failures appear suddenly---small errors that would show up without it are masked, and by the time you start seeing problems in the disk functionality it probably is too late to get all the data Google published a paper ( http://labs.google.com/papers/disk_failures.pdf ) looking at their statistics of disk failures---as you may imagine, they have tons of experience. They said that SMART doesn't predict all failures---some disks go bad without any warning whatsoever---but that sector reallocation events are a strong predictor if impending failure. They didn't publish manufacturer comparison for partly legal reasons, and partly because they claimed that there is no significant, consistent advantage to any particular one. ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
