From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: unreadable drives can be synchronized? Date: Wed, 23 May 2007 13:46:23 -0400 Message-ID: <46547DEF.8040403@tmr.com> References: <200705181447.l4IElO2a000640@cichlid.com> <464DC06F.2080609@wpkg.org> <7296208f0705181118n32537ddck4d94bed08625b79f@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7296208f0705181118n32537ddck4d94bed08625b79f@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Colin McCabe Cc: Tomasz Chmielewski , Andrew Burgess , linux-raid@vger.kernel.org List-Id: linux-raid.ids Colin McCabe wrote: > On 5/18/07, Tomasz Chmielewski wrote: >> Andrew Burgess schrieb: >> >> Basically, B appears to be "write-only"; it will never return an >> error on a >> >> write, but just try to read from it, and you will be sorry. >> > >> > It would be interesting to see what SMART says about drive B, >> especially >> > the short and long self tests. >> >> I wouldn't rely on SMART. >> >> I have a broken drive, which has lots of badblocks - but SMART happily >> claims it's fine (short/long tests are completed without errors). >> > > If you haven't seen Google's hard drive study yet, you should take a > look. > It's at http://labs.google.com/papers/disk_failures.pdf > > The conclusion says that "some of the SMART parameters are > well-correlated with higher failure probabilities," but also that "a > large fraction of [google's] failed drives have shown no SMART error > signals whatsoever." Having covered that in a presentation to a user group related to SMART. may I offer a paraphrase which may be more obvious to people who are not native speakers of English: High counts of some SMART parameters indicate that the drive is likely to fail. However, most drives fail without warning. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979