Hello, folks. What should I do about the following error? mdadm: ignoring /dev/sdd1 as it reports /dev/sdb1 as failed I'm building a new replacement array and restoring from backup, but I would still like to try and salvage this failed one if possible, and I was surprised to find very few results on google for that particular error message. Here is the background. I recently had a 4-disk raid5 array made up of: /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 Wednesday afternoon (yesterday), /dev/sde1 failed, so the array went into degraded (no parity) state. I thought I'd give sde another chance, so I zero'd the superblock and re-added it to the array, which began rebuilding. But then when it had reached 72.4% early this morning, /dev/sdb1 failed: md127 : active raid5 sde1[5] sdc1[0] sdb1[1](F) sdd1[4] 5859302400 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/2] [U__U] [==============>......] recovery = 72.4% (1414790348/1953100800) finish=1192.3min speed=7524K/sec But /dev/sdb1 is working now (same as /dev/sde1). I tried to re-assemble the raid: [root@lx4 ~]# mdadm --assemble --verbose /dev/md127 /dev/sd[bcde]1 mdadm: looking for devices for /dev/md127 mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 1. mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 0. mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 3. mdadm: /dev/sde1 is identified as a member of /dev/md127, slot -1. mdadm: added /dev/sdb1 to /dev/md127 as 1 (possibly out of date) mdadm: no uptodate device for slot 2 of /dev/md127 mdadm: added /dev/sdd1 to /dev/md127 as 3 mdadm: added /dev/sde1 to /dev/md127 as -1 mdadm: added /dev/sdc1 to /dev/md127 as 0 mdadm: /dev/md127 assembled from 2 drives and 1 spare - not enough to start the array. But it rejected /dev/sdb1, so I ran --force to have it update the event count: [root@lx4 ~]# mdadm --assemble --force --verbose /dev/md127 /dev/sd[bcde]1 mdadm: looking for devices for /dev/md127 mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 1. mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 0. mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 3. mdadm: /dev/sde1 is identified as a member of /dev/md127, slot -1. mdadm: forcing event count in /dev/sdb1(1) from 905199 upto 905262 mdadm: clearing FAULTY flag for device 0 in /dev/md127 for /dev/sdb1 mdadm: Marking array /dev/md127 as 'clean' mdadm: added /dev/sdb1 to /dev/md127 as 1 mdadm: no uptodate device for slot 2 of /dev/md127 mdadm: added /dev/sdd1 to /dev/md127 as 3 mdadm: added /dev/sde1 to /dev/md127 as -1 mdadm: added /dev/sdc1 to /dev/md127 as 0 mdadm: /dev/md127 assembled from 3 drives and 1 spare - not enough to start the array. This surprised me a lot, because I thought 3 drives would have been enough to start the array. But when I ran it again, I got a different error: [root@lx4 ~]# mdadm --assemble --force --verbose /dev/md127 /dev/sd[bcde]1 mdadm: looking for devices for /dev/md127 mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 1. mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 0. mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 3. mdadm: /dev/sde1 is identified as a member of /dev/md127, slot -1. mdadm: ignoring /dev/sdd1 as it reports /dev/sdb1 as failed mdadm: added /dev/sdb1 to /dev/md127 as 1 mdadm: no uptodate device for slot 2 of /dev/md127 mdadm: no uptodate device for slot 3 of /dev/md127 mdadm: added /dev/sde1 to /dev/md127 as -1 mdadm: added /dev/sdc1 to /dev/md127 as 0 mdadm: /dev/md127 assembled from 2 drives and 1 spare - not enough to start the array. It appears to be failing because of this: mdadm: ignoring /dev/sdd1 as it reports /dev/sdb1 as failed The sauce says this: /* If this device thinks that 'most_recent' has failed, then * we must reject this device. */ But I can't interpret that into a possible fix. Any ideas? Thanks in advance, -- Daniel Browning Appendix A. Versions Distro: Fedora Core 16 Kernel: 3.4.4-4.fc16.x86_64 #1 SMP Thu Jul 5 20:01:38 UTC 2012 mdadm: v3.2.5 - 18th May 2012 Appendix B. contents of mdstat after a failed "--assemble": md127 : inactive sdc1[0](S) sdb1[1](S) 3906202639 blocks super 1.2 Appendix C. mdadm --examine for all disks, from *before* the "--assemble --force" was executed: /dev/sdb1: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 4ca86345:c28c62be:03c9f77b:6760ef5c Name : lx4:127 Creation Time : Sun Oct 10 15:46:28 2010 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 3906202639 (1862.62 GiB 1999.98 GB) Array Size : 5859302400 (5587.87 GiB 5999.93 GB) Used Dev Size : 3906201600 (1862.62 GiB 1999.98 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 156bc6e0:eaa285fd:8f4ef720:6f2171c2 Update Time : Thu Jan 10 00:50:25 2013 Checksum : f0945b4a - correct Events : 905199 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 1 Array State : AAAA ('A' == active, '.' == missing) /dev/sdc1: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 4ca86345:c28c62be:03c9f77b:6760ef5c Name : lx4:127 Creation Time : Sun Oct 10 15:46:28 2010 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 3906202639 (1862.62 GiB 1999.98 GB) Array Size : 5859302400 (5587.87 GiB 5999.93 GB) Used Dev Size : 3906201600 (1862.62 GiB 1999.98 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 2dbbc5d0:f3deb841:50c7c992:c9abf856 Update Time : Thu Jan 10 09:14:03 2013 Checksum : 2b1b4f88 - correct Events : 905262 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 0 Array State : A..A ('A' == active, '.' == missing) /dev/sdd1: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 4ca86345:c28c62be:03c9f77b:6760ef5c Name : lx4:127 Creation Time : Sun Oct 10 15:46:28 2010 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 3906202639 (1862.62 GiB 1999.98 GB) Array Size : 5859302400 (5587.87 GiB 5999.93 GB) Used Dev Size : 3906201600 (1862.62 GiB 1999.98 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : bdd8c401:9389bf9b:c80762a2:682b0297 Update Time : Thu Jan 10 09:14:03 2013 Checksum : 5c2d7d3 - correct Events : 905262 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 3 Array State : A..A ('A' == active, '.' == missing) /dev/sde1: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 4ca86345:c28c62be:03c9f77b:6760ef5c Name : lx4:127 Creation Time : Sun Oct 10 15:46:28 2010 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 3906202639 (1862.62 GiB 1999.98 GB) Array Size : 5859302400 (5587.87 GiB 5999.93 GB) Used Dev Size : 3906201600 (1862.62 GiB 1999.98 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 78c381f7:1447cbd4:6af86729:d4c08320 Update Time : Thu Jan 10 09:14:03 2013 Checksum : 4513061e - correct Events : 905262 Layout : left-symmetric Chunk Size : 512K Device Role : spare Array State : A..A ('A' == active, '.' == missing) -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html