From mboxrd@z Thu Jan 1 00:00:00 1970 From: thomas62186218@aol.com Subject: Potential mdadm 2.6.7 bug: Cannot grow linear arrays with superblock v1.0, 1.1, or 1.2 Date: Tue, 14 Oct 2008 12:28:30 -0400 Message-ID: <8CAFC3107449F0E-C80-C20@mblk-d47.sysops.aol.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi all, I have come across what is a potential bug in mdadm 2.6.7. (unless I am missing something) Environment: Ubuntu Linux 8.0.4 64-bit (Hardy) Intel dual socket quad-core server with 16GB RAM 10 SATA II 500GB hard drives mdadm v2.6.7 Test 1: Attempt to grow linear md device with v1.0 superblock with additional hard drive. Failed. root@localhost:/usr/local/apache2/htdocs# mdadm --grow /dev/md6 --add /dev/sdd1 mdadm: internal error - sb_offset is wrong Aborted Test 2: Attempt to grow linear md device with v1.0 superblock with another linear md device with 1.0 superblock. Failed. root@localhost:/usr/local/apache2/htdocs# mdadm --grow /dev/md6 --add /dev/md5 mdadm: internal error - sb_offset is wrong Aborted Test 3: Attempt to grow linear md device with default 0.9 superblock with additional hard drive. Success. root@localhost:/usr/local/apache2/htdocs# mdadm -C -f -R /dev/md7 -l linear -n 2 /dev/sdb1 /dev/sdc1 mdadm: array /dev/md7 started. root@localhost:/usr/local/apache2/htdocs# mdadm --grow /dev/md7 --add /dev/sdd1 root@localhost:/usr/local/apache2/htdocs# cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md7 : active linear sdd1[2] sdc1[1] sdb1[0] 1025436608 blocks 64k rounding unused devices: I would appreciate any thoughts on this. I definitely want to use the more modern superblock version but I also need the ability to grow linear md's. Also, any plans on enabling "reshaping" or growth for RAID 0 and RAID 10 md's? Thanks! -Thomas