From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Deufel Subject: Reassembling Raid5 in degraded state Date: Mon, 13 Jan 2020 10:41:01 +0100 Message-ID: <54384251-9978-eb99-e7ec-2da35f41566c@inview.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi I'm having a problem with a 4 disk Raid 5 MD-Array. After a crash it didn't reassemble correctly, by that I mean it crashed during the reassemble, and cat /proc/mdstat reads as follows: [root@dirvish ~]# cat /proc/mdstat Personalities : [raid1] [raid0] [raid6] [raid5] [raid4] ... md3 : inactive sdd1[0] sde1[5] sdf1[3] sdc1[2]       7814047744 blocks ... mdadm --examine for the disks in the Raid reads as follows: [root@dirvish ~]# mdadm -E /dev/sdc1 /dev/sdc1:           Magic : a92b4efc         Version : 0.90.00            UUID : 84b70068:58203635:60d8aaf0:b60ee018   Creation Time : Mon Feb 28 18:46:58 2011      Raid Level : raid5   Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)      Array Size : 5860535808 (5589.04 GiB 6001.19 GB)    Raid Devices : 4   Total Devices : 4 Preferred Minor : 3     Update Time : Wed Jan  8 12:26:35 2020           State : clean  Active Devices : 3 Working Devices : 4  Failed Devices : 1   Spare Devices : 1        Checksum : bd93dda1 - correct          Events : 5995154          Layout : left-symmetric      Chunk Size : 64K       Number   Major   Minor   RaidDevice State this     2       8       33        2      active sync   /dev/sdc1    0     0       8       49        0      active sync   /dev/sdd1    1     1       0        0        1      faulty removed    2     2       8       33        2      active sync   /dev/sdc1    3     3       8       81        3      active sync   /dev/sdf1    4     4       8       65        4      spare   /dev/sde1 [root@dirvish ~]# mdadm -E /dev/sdd1 /dev/sdd1:           Magic : a92b4efc         Version : 0.90.00            UUID : 84b70068:58203635:60d8aaf0:b60ee018   Creation Time : Mon Feb 28 18:46:58 2011      Raid Level : raid5   Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)      Array Size : 5860535808 (5589.04 GiB 6001.19 GB)    Raid Devices : 4   Total Devices : 3 Preferred Minor : 3     Update Time : Wed Jan  8 13:30:15 2020           State : clean  Active Devices : 2 Working Devices : 2  Failed Devices : 2   Spare Devices : 0        Checksum : bd93ec60 - correct          Events : 5995162          Layout : left-symmetric      Chunk Size : 64K       Number   Major   Minor   RaidDevice State this     0       8       49        0      active sync   /dev/sdd1    0     0       8       49        0      active sync   /dev/sdd1    1     1       0        0        1      faulty removed    2     2       0        0        2      faulty removed    3     3       8       81        3      active sync   /dev/sdf1 [root@dirvish ~]# mdadm -E /dev/sde1 /dev/sde1:           Magic : a92b4efc         Version : 0.90.00            UUID : 84b70068:58203635:60d8aaf0:b60ee018   Creation Time : Mon Feb 28 18:46:58 2011      Raid Level : raid5   Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)      Array Size : 5860535808 (5589.04 GiB 6001.19 GB)    Raid Devices : 4   Total Devices : 3 Preferred Minor : 3     Update Time : Wed Jan  8 13:30:15 2020           State : clean  Active Devices : 2 Working Devices : 2  Failed Devices : 2   Spare Devices : 0        Checksum : bd93ecbd - correct          Events : 5995162          Layout : left-symmetric      Chunk Size : 64K       Number   Major   Minor   RaidDevice State this     5       8       65       -1      spare   /dev/sde1    0     0       8       49        0      active sync   /dev/sdd1    1     1       0        0        1      faulty removed    2     2       0        0        2      faulty removed    3     3       8       81        3      active sync   /dev/sdf1 [root@dirvish ~]# mdadm -E /dev/sdf1 /dev/sdf1:           Magic : a92b4efc         Version : 0.90.00            UUID : 84b70068:58203635:60d8aaf0:b60ee018   Creation Time : Mon Feb 28 18:46:58 2011      Raid Level : raid5   Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)      Array Size : 5860535808 (5589.04 GiB 6001.19 GB)    Raid Devices : 4   Total Devices : 3 Preferred Minor : 3     Update Time : Wed Jan  8 13:30:15 2020           State : clean  Active Devices : 2 Working Devices : 2  Failed Devices : 2   Spare Devices : 0        Checksum : bd93ec86 - correct          Events : 5995162          Layout : left-symmetric      Chunk Size : 64K       Number   Major   Minor   RaidDevice State this     3       8       81        3      active sync   /dev/sdf1    0     0       8       49        0      active sync   /dev/sdd1    1     1       0        0        1      faulty removed    2     2       0        0        2      faulty removed    3     3       8       81        3      active sync   /dev/sdf1 My plan now would be to run mdadm --assemble --force /dev/md3 with 3 disk, to get the Raid going in a degraded state. Does anyone have any experience in doing so and can recommend which 3 disks I should use. I would use sdc1 sdd1 and sdf1, since sdd1 and sdf1 are displayed as active sync in every examine and sdc1 as it is also displayed as active sync. Do you think that by doing it this way I have a chance to get my Data back or do you have any other suggestion as to get the Data back and the Raid running again? Greetings Christian  ------------------------------------------------------------------- | Christian Deufel | | | inView Groupware und Datentechnik GmbH | Emmy-Noether-Str.2 | 79110 Freiburg | | https://www.inView.de | christian.deufel@inView.de | Tel. 0761 - 45 75 48-22 | Fax. 0761 - 45 75 48-99 | | Amtsgericht Freiburg HRB-6769 | Ust-ID DE 219531868 | Geschäftsführer: Caspar Fromelt, Frank Kopp  -------------------------------------------------------------------