Hey guys, I'm in a bit of a pickle here and if any mdadm kings could step in and throw some advice my way I'd be very grateful :-) Quick bit of background - little NAS based on an AMD E350 running Ubuntu 10.04. Running a software RAID 5 from 5x2TB disks. Every few months one of the drives would fail a request and get kicked from the array (as is becoming common for these larger multi TB drives they tolerate the occasional bad sector by reallocating from a pool of spares (but that's a whole other story)). This happened across a variety of brands and two different controllers. I'd simply add the disk that got popped back in and let it re-sync. SMART tests always in good health. It did make me nervous though. So I decided I'd add a second disk for a bit of extra redundancy, making the array a RAID 6 - the thinking was the occasional disk getting kicked and re-added from a RAID 6 array wouldn't present as much risk as a single disk getting kicked from a RAID 5. So first off, I added the 6th disk as a hotspare to the RAID5 array. So I now had my 5 disk RAID 5 + hotspare. I then found that mdadm 2.6.7 (in the repositories) isn't actually capable of a 5->6 reshape. So I pulled the latest 3.2.3 sources and compiled myself a new version of mdadm. With the newer version of mdadm, it was happy to do the reshape - so I set it off on it's merry way, using an esata HD (mounted at /usb :-P) for the backupfile: root@raven:/# mdadm --grow /dev/md0 --level=6 --raid-devices=6 --backup-file=/usb/md0.backup It would take a week to reshape, but it was ona UPS & happily ticking along. The array would be online the whole time so I was in no rush. Content, I went to get some shut-eye. I got up this morning and took a quick look in /proc/mdstat to see how things were going and saw things had failed spectacularly. At least two disks had been kicked from the array and the whole thing had crumbled. Ouch. I tried to assembe the array, to see if it would continue the reshape: root@raven:/# mdadm -Avv --backup-file=/usb/md0.backup /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sdf1 /dev/sdg1 Unfortunately mdadm had decided that the backup-file was out of date (timestamps didn't match) and was erroring with: Failed to restore critical section for reshape, sorry.. Chances are things were in such a mess that backup file wasn't going to be used anyway, so I blocked the timestamp check with: export MDADM_GROW_ALLOW_OLD=1 That allowed me to assemble the array, but not run it as there were not enough disks to start it. This is the current state of the array: Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdb1[1] sdd1[5] sdf1[4] sda1[2] 7814047744 blocks super 0.91 unused devices: <none> root@raven:/# mdadm --detail /dev/md0 /dev/md0: Version : 0.91 Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Raid Devices : 6 Total Devices : 4 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Tue Feb 7 09:32:29 2012 State : active, FAILED, Not Started Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric-6 Chunk Size : 64K New Layout : left-symmetric UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Events : 0.1848341 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1 2 8 1 2 active sync /dev/sda1 3 0 0 3 removed 4 8 81 4 active sync /dev/sdf1 5 8 49 5 spare rebuilding /dev/sdd1 The two removed disks: [ 3020.998529] md: kicking non-fresh sdc1 from array! [ 3021.012672] md: kicking non-fresh sdg1 from array! Attempted to re-add the disks (same for both): root@raven:/# mdadm /dev/md0 --add /dev/sdg1 mdadm: /dev/sdg1 reports being an active member for /dev/md0, but a --re-add fails. mdadm: not performing --add as that would convert /dev/sdg1 in to a spare. mdadm: To make this a spare, use "mdadm --zero-superblock /dev/sdg1" first. With a failed array the last thing we want to do is add spares and trigger a resync so obviously I haven't zeroed the superblocks and added yet. Checked and two disks really are out of sync: root@raven:/# mdadm --examine /dev/sd[a-h]1 | grep Event Events : 1848341 Events : 1848341 Events : 1848333 Events : 1848341 Events : 1848341 Events : 1772921 I'll post the output of --examine on all the disks below - if anyone has any advice I'd really appreciate it (Neil Brown doesn't read these forums does he?!?). I would usually move next to recreating the array and using assume-clean but since it's right in the middle of a reshape I'm not inclined to try. Critical stuff is of course backed up, but there is some user data not covered by backups that I'd like to try and restore if at all possible. Thanks root@raven:/# mdadm --examine /dev/sd[a-h]1 /dev/sda1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 09:32:29 2012 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : 3c0c8563 - correct Events : 1848341 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 2 8 17 2 active sync /dev/sdb1 0 0 0 0 0 removed 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 0 0 3 faulty removed 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 /dev/sdb1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 09:32:29 2012 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : 3c0c8571 - correct Events : 1848341 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 1 8 33 1 active sync /dev/sdc1 0 0 0 0 0 removed 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 0 0 3 faulty removed 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 /dev/sdc1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 07:12:01 2012 State : clean Active Devices : 5 Working Devices : 5 Failed Devices : 0 Spare Devices : 0 Checksum : 3c0c6478 - correct Events : 1848333 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 49 3 active sync /dev/sdd1 0 0 0 0 0 removed 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 8 49 3 active sync /dev/sdd1 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 /dev/sdd1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 09:32:29 2012 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : 3c0c8595 - correct Events : 1848341 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 5 8 65 5 active /dev/sde1 0 0 0 0 0 removed 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 0 0 3 faulty removed 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 /dev/sdf1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 09:32:29 2012 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : 3c0c85a7 - correct Events : 1848341 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 4 8 81 4 active sync /dev/sdf1 0 0 0 0 0 removed 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 0 0 3 faulty removed 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 /dev/sdg1: Magic : a92b4efc Version : 0.91.00 UUID : 9a76d1bd:2aabd685:1fc5fe0e:7751cfd7 (local to host raven) Creation Time : Tue Jul 12 23:05:01 2011 Raid Level : raid6 Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Reshape pos'n : 307740672 (293.48 GiB 315.13 GB) New Layout : left-symmetric Update Time : Tue Feb 7 01:06:46 2012 State : clean Active Devices : 6 Working Devices : 6 Failed Devices : 0 Spare Devices : 0 Checksum : 3c09c1d2 - correct Events : 1772921 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 0 8 97 0 active sync /dev/sdg1 0 0 8 97 0 active sync /dev/sdg1 1 1 8 33 1 active sync /dev/sdc1 2 2 8 17 2 active sync /dev/sdb1 3 3 8 49 3 active sync /dev/sdd1 4 4 8 81 4 active sync /dev/sdf1 5 5 8 65 5 active /dev/sde1 -- 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
