From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Why does one get mismatches? Date: Mon, 01 Feb 2010 16:10:15 -0500 Message-ID: <4B674337.4090900@tmr.com> References: <166572.83607.qm@web51301.mail.re2.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <166572.83607.qm@web51301.mail.re2.yahoo.com> Sender: linux-raid-owner@vger.kernel.org To: Jon@eHardcastle.com Cc: linux-raid@vger.kernel.org, Goswin von Brederlow List-Id: linux-raid.ids Jon Hardcastle wrote: > --- On Thu, 28/1/10, Goswin von Brederlow wrote: > > >> From: Goswin von Brederlow >> Subject: Re: Why does one get mismatches? >> To: linux-raid@vger.kernel.org >> Date: Thursday, 28 January, 2010, 20:24 >> "Tirumala Reddy Marri" >> writes: >> >> >>> I just tried and miss-match count is zero. >>> >> Interesting, is XOR engine >> >>> doing something wrong ? . Then I ran a test where I >>> >> raw-write the file >> >>> to /dev/md0. Then did the raw-read for the same size. >>> >> In this case XOR >> >>> matched as expected. Then I failed a drive using >>> >> "mdadm -f /dev/md0 >> >>> /dev/sda". Then I read the same size data again from >>> >> /dev/md0. And >> >>> checksum matches too. >>> What is this mean XOR engine is doing right thing. But >>> >> "chec/repair" >> >>> test is not functioning properly with XOR-engine ? >>> >>> Or is this something to do with how the buffers >>> >> are handled ? may they >> >>> are cached ? >>> >>> >>> -Marri >>> >> No idea. But if everything works without the XOR engine and >> gives >> mismatches with then I would think there is a software or >> hardware error >> there and not in the cable or disks. >> >> MfG >> Goswin >> -- >> 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 >> >> > > i think my RAM is fecked - does that sound like a possible cause? memtest86 gives PAGES of red errors when run but the POST gives nothing and the machine boots.... it has 512MB > > i have some more on order as a speculative.. > I would bet that your RAM is broken. Any errors indicate bad RAM, no errors indicate no persistent error. Scrap that RAM. More will make the machine faster, too. -- Bill Davidsen "We can't solve today's problems by using the same thinking we used in creating them." - Einstein