From: Andreas Dilger Subject: Re: ext4 corruption on md [7x1TB in RAID5] Date: Sat, 09 May 2009 12:56:15 -0600 Message-ID: <20090509185615.GN3209@webber.adilger.int> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: linux-ext4@vger.kernel.org To: Don Bowman Return-path: Received: from sca-es-mail-1.Sun.COM ([192.18.43.132]:61035 "EHLO sca-es-mail-1.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752218AbZEIS40 (ORCPT ); Sat, 9 May 2009 14:56:26 -0400 Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-1.sun.com (8.13.7+Sun/8.12.9) with ESMTP id n49IuRMf010289 for ; Sat, 9 May 2009 11:56:27 -0700 (PDT) Content-disposition: inline Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java(tm) System Messaging Server 7.0-5.01 64bit (built Feb 19 2009)) id <0KJE00A004LLA000@fe-sfbay-09.sun.com> for linux-ext4@vger.kernel.org; Sat, 09 May 2009 11:56:27 -0700 (PDT) In-reply-to: Sender: linux-ext4-owner@vger.kernel.org List-ID: On May 09, 2009 14:36 -0400, Don Bowman wrote: > To follow my own email, the results of the 'findsuper' program are: > > starting at 0, with 512 byte increments > byte_offset byte_start byte_end fs_blocks blksz grp last_mount_time sb_uuid label > 1024 0 6001228775424 1465143744 4096 0 Wed Apr 22 19:04:50 2009 52e18bf7 > 134217728 0 6001228775424 1465143744 4096 1 Wed Apr 22 19:04:50 2009 52e18bf7 > 402653184 0 6001228775424 1465143744 4096 3 Wed Apr 22 19:04:50 2009 52e18bf7 > 671088640 0 6001228775424 1465143744 4096 5 Wed Apr 22 19:04:50 2009 52e18bf7 > 939524096 0 6001228775424 1465143744 4096 7 Wed Apr 22 19:04:50 2009 52e18bf7 > 1207959552 0 6001228775424 1465143744 4096 9 Wed Apr 22 19:04:50 2009 52e18bf7 > 3355443200 0 6001228775424 1465143744 4096 25 Wed Apr 22 19:04:50 2009 52e18bf7 > 3623878656 0 6001228775424 1465143744 4096 27 Wed Apr 22 19:04:50 2009 52e18bf7 > 6576668672 0 6001228775424 1465143744 4096 49 Wed Apr 22 19:04:50 2009 52e18bf7 > 10871635968 0 6001228775424 1465143744 4096 81 Wed Apr 22 19:04:50 2009 52e18bf7 > 16777216000 0 6001228775424 1465143744 4096 125 Wed Apr 22 19:04:50 2009 52e18bf7 > 32614907904 0 6001228775424 1465143744 4096 243 Wed Apr 22 19:04:50 2009 52e18bf7 > 46036680704 0 6001228775424 1465143744 4096 343 Wed Apr 22 19:04:50 2009 52e18bf7 > 83886080000 0 6001228775424 1465143744 4096 625 Wed Apr 22 19:04:50 2009 52e18bf7 > 97844723712 0 6001228775424 1465143744 4096 729 Wed Apr 22 19:04:50 2009 52e18bf7 > ... [still going] > > Can this help me somehow? These are all showing available backup superblocks and group descriptors. Pick one of the "grp" numbers and use that as the argument for "-b" per my previous email: "e2fsck -f -b $((729 * 32768)) -B 4096 /dev/XXX". A backup first is still a good idea, however. Note that this appears to be a bug that has been hit by several Ubuntu users. I would suggest to upgrade to the latest vanilla kernel (at least 2.6.29.stable, search the archives for details), which has fixed it for many users. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc.