Re: looking for advice on raid0+raid5 array recovery with mdadm and sector offset
From: NeilBrown <hidden>
Date: 2014-01-06 01:41:43
On Thu, 2 Jan 2014 20:45:24 +0100 den Hoog [off-list ref] wrote:
Hi Neil I apologize if I made mistakes with the first mail post but probably something went wrong, so this is a retry. I'm looking for advice on my plan to recover my raid5 volume with mdadm. I was in a hurry and made a stupid mistake when upgrading the MB bios. Forgot to turn on the Intel SATA raid, and Windows recovery erased the first disk of 4. It is an array of 4x4TB, in a matrix, having 1 RAID0 volume, and 1 RAID5 vol. Although the array displays a failed array in Windows, 3 disks are active, and 1 is missing and showing as a non-raid array being available. In (my) theory, I should still be able to recover the raid5 vol. with the remaining 3 disks, however I should specify the specific sector offset I guess. I read many articles on this, but none of them address the 'difficulty' of recovering a specific volume when multiple exist in an array. Although I've some backups, I really would appreciate your help in getting this recovered. sda is the SSD sdb is the 'missing' and erased drive (serial ending on P82C) sdc is the second drive in the array sdd is the 3rd drive in the array sde is the 4th drive in the array sdf is the usb stick I'm running Fedora live from What I've done so far : - Started Fedora 15 Live from a USB - installed the mdadm package data_offset and compiled My plan to work with an offset to recover the [HitR5] volume: - echo 1 > /sys/module/md_mod/parameters/ start_dirty_degraded - mdadm -C /dev/md/imsm -e imsm -n 4 /dev/sdb /dev/sdc /dev/sdd /dev/sde - mdadm -C /dev/md0 -l5 -n4 -c 128 /dev/sdb:1073746184s /dev/sdc:1073746184s /dev/sdd:1073746184s /dev/sde:1073746184s
This certainly won't work. You need "--data-offset=variable" for the "NNNNs" suffixes to be recognised, and even then it only works for 1.x metadata, not for imsm metadata. There isn't much support for sticking together broken IMSM arrays at present. Your best bet is to re-create the whole array. So: mdadm -C /dev/md/imsm -e imsm -n 4 /dev/sd[bcde] mdadm -C /dev/md0 -l0 -n4 -c 128K -z 512G /dev/md/imsm then check that /dev/md0 looks OK for the RAID0 array. If it does then you can continue to create the raid5 array mdadm -C /dev/md1 -l5 -n4 -c 128k --assume-clean /dev/md/imsm That *should* then be correct. If the RAID0 array doesn't look right, the possible sdb really was cleared rather than just having the metadata erased. In this case the RAID0 is definitely gone and it will be a bit harder to create the RAID5. It could be something like: mdadm -C /dev/md1 -l5 -n4 -c 128k missing /dev/sd[cde] but I'm not sure that 'missing' is works for imsm. If you need to go this way I can try to make 'missing' for for imsm. It shouldn't be too hard. NeilBrown
I'm in doubt about working with missing disks first to start a
degraded array, with -C and missing for the first drive.
Or choosing assemble --auto, or as stated above and create the volume with an
offset.
Another thing I'm not certain of: do I need to build a new mdadm with
data_offset, or is it already present in my 3.2.6 version?
When I built a new version with Neils mdadm I ended up with a 3.2.5 18May2012
version.
As I guess I have only one shot at this I have not executed anything yet.
thanks many for your help, time and advice!
best regards Dennis
=======output mdadm -Evvvvs=============
root@localhost ~]# mdadm -Evvvvs
mdadm: No md superblock detected on /dev/dm-1.
mdadm: No md superblock detected on /dev/dm-0.
/dev/sdf1:
MBR Magic : aa55
Partition[0] : 432871117 sectors at 3224498923 (type 07)
Partition[1] : 1953460034 sectors at 3272020941 (type 16)
Partition[3] : 924335794 sectors at 50200576 (type 00)
/dev/sdf:
MBR Magic : aa55
Partition[0] : 15769600 sectors at 2048 (type 0b)
/dev/sde:
Magic : Intel Raid ISM Cfg Sig.
Version : 1.3.00
Orig Family : f3437c9b
Family : f3437c9d
Generation : 00002c5f
Attributes : All supported
UUID : 47b011c7:4a8531ea:7e94ab93:06034952
Checksum : 671f5f84 correct
MPB Sectors : 2
Disks : 4
RAID Devices : 2
Disk03 Serial : PL1321LAG4RXEH
State : active
Id : 00000005
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
[HitR0]:
UUID : 73ecf2cf:fcfd2598:d6523381:71e57931
RAID Level : 0
Members : 4
Slots : [_UUU]
Failed disk : 1
This Slot : 3
Array Size : 4294967296 (2048.00 GiB 2199.02 GB)
Per Dev Size : 1073742088 (512.00 GiB 549.76 GB)
Sector Offset : 0
Num Stripes : 4194304
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
[HitR5]:
UUID : 71626250:b8fc1262:3545d952:69eb329e
RAID Level : 5
Members : 4
Slots : [_UU_]
Failed disk : 3
This Slot : 3 (out-of-sync)
Array Size : 20220831744 (9642.04 GiB 10353.07 GB)
Per Dev Size : 6740279304 (3214.02 GiB 3451.02 GB)
Sector Offset : 1073746184
Num Stripes : 26329208
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
Disk00 Serial : PL2311LAG1P82C:0
State : active
Id : ffffffff
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk01 Serial : PL1321LAG4NMEH
State : active
Id : 00000003
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk02 Serial : PL1321LAG4TH4H
State : active
Id : 00000004
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
/dev/sdd:
Magic : Intel Raid ISM Cfg Sig.
Version : 1.3.00
Orig Family : f3437c9b
Family : f3437c9d
Generation : 00002c5f
Attributes : All supported
UUID : 47b011c7:4a8531ea:7e94ab93:06034952
Checksum : 671f5f84 correct
MPB Sectors : 2
Disks : 4
RAID Devices : 2
Disk02 Serial : PL1321LAG4TH4H
State : active
Id : 00000004
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
[HitR0]:
UUID : 73ecf2cf:fcfd2598:d6523381:71e57931
RAID Level : 0
Members : 4
Slots : [_UUU]
Failed disk : 1
This Slot : 2
Array Size : 4294967296 (2048.00 GiB 2199.02 GB)
Per Dev Size : 1073742088 (512.00 GiB 549.76 GB)
Sector Offset : 0
Num Stripes : 4194304
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
[HitR5]:
UUID : 71626250:b8fc1262:3545d952:69eb329e
RAID Level : 5
Members : 4
Slots : [_UU_]
Failed disk : 3
This Slot : 2
Array Size : 20220831744 (9642.04 GiB 10353.07 GB)
Per Dev Size : 6740279304 (3214.02 GiB 3451.02 GB)
Sector Offset : 1073746184
Num Stripes : 26329208
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
Disk00 Serial : PL2311LAG1P82C:0
State : active
Id : ffffffff
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk01 Serial : PL1321LAG4NMEH
State : active
Id : 00000003
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk03 Serial : PL1321LAG4RXEH
State : active
Id : 00000005
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
/dev/sdc:
Magic : Intel Raid ISM Cfg Sig.
Version : 1.3.00
Orig Family : f3437c9b
Family : f3437c9d
Generation : 00002c5f
Attributes : All supported
UUID : 47b011c7:4a8531ea:7e94ab93:06034952
Checksum : 671f5f84 correct
MPB Sectors : 2
Disks : 4
RAID Devices : 2
Disk01 Serial : PL1321LAG4NMEH
State : active
Id : 00000003
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
[HitR0]:
UUID : 73ecf2cf:fcfd2598:d6523381:71e57931
RAID Level : 0
Members : 4
Slots : [_UUU]
Failed disk : 1
This Slot : 1
Array Size : 4294967296 (2048.00 GiB 2199.02 GB)
Per Dev Size : 1073742088 (512.00 GiB 549.76 GB)
Sector Offset : 0
Num Stripes : 4194304
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
[HitR5]:
UUID : 71626250:b8fc1262:3545d952:69eb329e
RAID Level : 5
Members : 4
Slots : [_UU_]
Failed disk : 3
This Slot : 1
Array Size : 20220831744 (9642.04 GiB 10353.07 GB)
Per Dev Size : 6740279304 (3214.02 GiB 3451.02 GB)
Sector Offset : 1073746184
Num Stripes : 26329208
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
Disk00 Serial : PL2311LAG1P82C:0
State : active
Id : ffffffff
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk02 Serial : PL1321LAG4TH4H
State : active
Id : 00000004
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk03 Serial : PL1321LAG4RXEH
State : active
Id : 00000005
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
mdadm: No md superblock detected on /dev/sdb1.
/dev/sdb:
MBR Magic : aa55
Partition[0] : 4294967295 sectors at 1 (type ee)
/dev/sda2:
MBR Magic : aa55
Partition[0] : 1816210284 sectors at 1920221984 (type 72)
Partition[1] : 1953653108 sectors at 1936028192 (type 6c)
Partition[3] : 447 sectors at 27722122 (type 00)
/dev/sda1:
MBR Magic : aa55
Partition[0] : 1816210284 sectors at 1920221984 (type 72)
Partition[1] : 1953653108 sectors at 1936028192 (type 6c)
Partition[3] : 447 sectors at 27722122 (type 00)
/dev/sda:
MBR Magic : aa55
Partition[0] : 716800 sectors at 2048 (type 07)
Partition[1] : 499396608 sectors at 718848 (type 07)
mdadm: No md superblock detected on /dev/loop4.
mdadm: No md superblock detected on /dev/loop3.
mdadm: No md superblock detected on /dev/loop2.
mdadm: No md superblock detected on /dev/loop1.
mdadm: No md superblock detected on /dev/loop0.
/dev/md127:
Magic : Intel Raid ISM Cfg Sig.
Version : 1.3.00
Orig Family : f3437c9b
Family : f3437c9d
Generation : 00002c5f
Attributes : All supported
UUID : 47b011c7:4a8531ea:7e94ab93:06034952
Checksum : 671f5f84 correct
MPB Sectors : 2
Disks : 4
RAID Devices : 2
Disk02 Serial : PL1321LAG4TH4H
State : active
Id : 00000004
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
[HitR0]:
UUID : 73ecf2cf:fcfd2598:d6523381:71e57931
RAID Level : 0
Members : 4
Slots : [_UUU]
Failed disk : 1
This Slot : 2
Array Size : 4294967296 (2048.00 GiB 2199.02 GB)
Per Dev Size : 1073742088 (512.00 GiB 549.76 GB)
Sector Offset : 0
Num Stripes : 4194304
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
[HitR5]:
UUID : 71626250:b8fc1262:3545d952:69eb329e
RAID Level : 5
Members : 4
Slots : [_UU_]
Failed disk : 3
This Slot : 2
Array Size : 20220831744 (9642.04 GiB 10353.07 GB)
Per Dev Size : 6740279304 (3214.02 GiB 3451.02 GB)
Sector Offset : 1073746184
Num Stripes : 26329208
Chunk Size : 128 KiB
Reserved : 0
Migrate State : idle
Map State : failed
Dirty State : clean
Disk00 Serial : PL2311LAG1P82C:0
State : active
Id : ffffffff
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk01 Serial : PL1321LAG4NMEH
State : active
Id : 00000003
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
Disk03 Serial : PL1321LAG4RXEH
State : active
Id : 00000005
Usable Size : 7814030862 (3726.02 GiB 4000.78 GB)
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