From owner-freebsd-questions@FreeBSD.ORG Mon Jul 18 14:49:29 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E407B106564A for ; Mon, 18 Jul 2011 14:49:29 +0000 (UTC) (envelope-from D.Forsyth@ru.ac.za) Received: from f.mail.ru.ac.za (f.mail.ru.ac.za [IPv6:2001:4200:1010::25:6]) by mx1.freebsd.org (Postfix) with ESMTP id 027BF8FC08 for ; Mon, 18 Jul 2011 14:49:29 +0000 (UTC) Received: from iwr.ru.ac.za ([146.231.64.249]:56029) by f.mail.ru.ac.za with esmtp (Exim 4.75 (FreeBSD)) (envelope-from ) id 1Qip8P-000FoY-MT for freebsd-questions@freebsd.org; Mon, 18 Jul 2011 16:49:25 +0200 Received: from iwdf-5.iwr.ru.ac.za ([146.231.64.28]) by iwr.ru.ac.za with esmtp (Exim 4.76 (FreeBSD)) (envelope-from ) id 1Qip8P-000GKO-LF for freebsd-questions@freebsd.org; Mon, 18 Jul 2011 16:49:25 +0200 From: "DA Forsyth" Organization: IWR To: freebsd-questions@freebsd.org Date: Mon, 18 Jul 2011 16:49:25 +0200 MIME-Version: 1.0 Message-ID: <4E2447F5.24958.3553D439@d.forsyth.ru.ac.za> Priority: normal X-mailer: Pegasus Mail for Windows (4.52) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body X-Virus-Scanned: f.mail.ru.ac.za (146.231.129.38) Subject: how to fix bad superblock X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: d.forsyth@ru.ac.za List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jul 2011 14:49:30 -0000 Hiya all After a hardrive let the smoke out last week, part of a 4 drive RAID array, I am now battling to get back into the array. I have replaced the bad drive and it has been rebuilt (Intel Matrix Raid on the motherboard). some partitions are ok but had lots of errors fsck fixed, others report ** /dev/ar0s1f BAD SUPER BLOCK: VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE it then asks if it must look for alternates but claims 32 is not one and stops. All my partitions are UFS so why doesn't it look at block 160? 'newfs -N ar0s1f' displays a lot of copies of the superblock. Google show that this error happens to a lot of folks,a nd there is no tool for fixing it. fsck_ufs will use an alternate superblock, prompt you to update the master block, and then NOT do it, the error persists. I used a dd command I found on the web to copy an alternate SB to the master superblock, and fsck still shows the message as above. I then copied the 2nd alternate to both the master and the 1nd alternate superblock positions, and it STILL reports a mismatch. Please tell me, how do I fix this. ar0s1f is discardable which is why I am trying to fix it first. /home has stuff I want to recover and it also has a bad superblock. The stuff I googled shows that there is confusion about block sizes. When 'newfs -N' shows a copy at block 160, what block size does it mean? the 16384 it shows in its display for this partition, or the default of 512? Thanks -- DA Fo rsyth Network Supervisor Principal Technical Officer -- Institute for Water Research http://www.ru.ac.za/institutes/iwr/