From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krekna Mektek Subject: Re: RAID 5 inaccessible - continued Date: Tue, 14 Feb 2006 18:18:02 +0100 Message-ID: <8b24c8b10602140918s136b5075s@mail.gmail.com> References: <8b24c8b10602130708p3e2f9a1dh@mail.gmail.com> <8b24c8b10602140035t5ca2e41cv@mail.gmail.com> <17393.42370.394254.464935@cse.unsw.edu.au> <8b24c8b10602140235s7a4ef1fam@mail.gmail.com> <43F1FFE1.2010107@h3c.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: <43F1FFE1.2010107@h3c.com> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Mike Hardy , linux-raid@vger.kernel.org List-Id: linux-raid.ids 2006/2/14, Mike Hardy : > > > Krekna Mektek wrote: > > > The dd actually succeeded, and did finish the job in about one day. > > The badblocks were found after about the first 7 Gigs. > > Is this a 3-disk raid5 array? With two healthy disks and one bad disk? Hi Mike! It is a 3 disk array, that is one spare (which was set as spare by Linux, previously marked as faulty I guess. This disk is probably out of date, because I don't know when this did happen, and I don't have the logs anymore). One disk is okay, and the faulty is probably also okay, except for the 76 bad sectors. I want to rebuilt from the good one and the faulty one. That's why I wanted to dd the disk to an image file, but it complains it has no boot sector. In this case, I actually *can* try the 2.6.15+ kernel then? Because the rebuilt *IS* working, except for the fact that it stops at 1,7%, which happens to be at the bad block area indeed. So, there actually IS a possibility now I was requesting for: mdadm to skip over the bad blocks area? That mean I can try again, but now with 2.6.15? And if not. I still don't understand why this did not work: > > > I did the folowing: > > > > > > dd conv=noerror if=dev/hdd1 of=/mnt/hdb1/Faulty-RAIDDisk.img > > > losetup /dev/loop0 /mnt/hdb1/Faulty-RAIDDisk.img > .. > > > > > > But it did not work out (yet). > > > > > > madm -E /dev/loop0 > > > mdadm: No super block found on /dev/loop0 (Expected magic a92b4efc, > > > got 00000000) Thanks for your help! Krekna > > If so, then what you really want is a new kernel (2.6.15+? 2.6.14+?) > that has raid5 read-error-handling code in it. Neil just coded that up. > > If it's missing a disk and has a disk with bad sectors, then you've > already lost data, but you could use a combination of smart tests and dd > to zero out those specific sectors (and only those sectors...) then sync > a new disk up with the array... > > -Mike >