From mboxrd@z Thu Jan 1 00:00:00 1970 From: Redeeman Subject: Re: detection/correction of corruption with raid6 Date: Fri, 05 Dec 2008 22:12:38 +0100 Message-ID: <1228511558.16555.84.camel@localhost> References: <1228510833.16555.76.camel@localhost> <1228511195.16555.78.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Justin Piszcz Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, 2008-12-05 at 16:09 -0500, Justin Piszcz wrote: > > On Fri, 5 Dec 2008, Redeeman wrote: > > > On Fri, 2008-12-05 at 16:02 -0500, Justin Piszcz wrote: > >> > >> On Fri, 5 Dec 2008, Redeeman wrote: > >> > >>> Hello. > >>> > >>> I was looking at the PDFs linked to from the wiki, and found this: > >>> http://kernel.org/pub/linux/kernel/people/hpa/raid6.pdf > >>> > >>> More specifically, section 4, starting on page 8. > >>> > >>> Am I understanding this correctly, in that with raid6, linux is capable > >>> of detecting if the content on 1 disk is corrupted, and reconstruct it > >>> from the remaining disks? > >> > >> I ran md/raid6 for awhile, do you mean remap the bad sector on the fly? > >> Linux/md raid does not do this afaik. > > > > No, i mean, if one disk does silent corruption > > What would the error look like? Both md/Linux & in the 3ware manual > recommend you run a 'check' across the raid at least once a week > (3ware/raid-verify) and md/Linux in Debian runs a check once a month I > believe to eliminate these issues. > > If you are asking whether a read error of a latent sector from the one > disk will result it reading the data from the second disk that is a good > question. im asking, if one disk in a raid6 setup suddenly decides to flip a few bits in some bytes, will it be able to detect that in a scan, and correct it? i cant see how it can do it on raid5, but maybe raid6? > > Justin. > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html