Hello All,
In the past, I was an active member of this forum, but I dropped
off for a few years. I am back now because I have an issue with which I
hope someone here can help me. I have a PC which has an LSI MegaRAID
9266-4i controller running RAID-5 on four drives, and unfortunately two
of the four drives failed more or less simultaneously. One of the
drives, however, was not completely dead, and with some time and a
little babying, I was able to recover most of the important sections of
one of the drives to a file using ddrescue. Unfortunately, I am having
trouble getting the array to assemble properly after copying the file
back to a drive using dd.
I am hoping to be able to assemble the drive images under mdadm,
but so far I am not getting the assembly to work, I think perhaps
because not all the necessary information is available to mdadm during
assembly. I created file images of both good drives and then I created
loop devices from all three images and assembled using
mdadm -A --force /dev/md7 /dev/loop0 /dev/loop1 /dev/loop2
When I examine the array, I get:
RAID-Server:/RAID/Server-Main/Temp# mdadm -D /dev/md7
/dev/md7:
Version : ddf
Raid Level : container
Total Devices : 3
Working Devices : 3
Container GUID : 4C534920:20202020:1000005B:10009269:4974DEC4:0689B9A9
(LSI 01/19/19 14:12:52)
Seq : 0000000b
Virtual Disks : 1
Member Arrays :
Number Major Minor RaidDevice
0 7 1 - /dev/loop1
1 7 2 - /dev/loop2
2 7 0 - /dev/loop0
Looking at the loop devices themselves I get:
RAID-Server:/RAID/Server-Main/Temp# mdadm -E /dev/loop0 /dev/loop1
/dev/loop2
/dev/loop0:
Magic : de11de11
Version : 01.00.00
Controller GUID : 4C534920:20202020:53563632:38343632:35370000:20300000
(LSI SV62846257)
Container GUID : 4C534920:20202020:1000005B:10009269:4974DEC4:0689B9A9
(LSI 01/19/19 14:12:52)
Seq : 0000000b
Redundant hdr : yes
Virtual Disks : 1
VD GUID[0] : 4C534920:20202020:1000005B:10009269:48421933:6EAADB6C
(LSI 05/31/18 22:36:19)
unit[0] : 0
state[0] : Degraded, Consistent
init state[0] : Not Initialised
access[0] : Read/Write
Name[0] :
Raid Devices[0] : 4 (0@0K 1@0K 2@0K --@0K)
Chunk Size[0] : 1024 sectors
Raid Level[0] : RAID5
Device Size[0] : 116686848
Array Size[0] : 350060544
Physical Disks : 255
Number RefNo Size Device Type/State
0 b99f8876 116686848K /dev/loop0 active/Online
1 b99f8877 116686848K active/Online
2 b99f8878 116686848K active/Online
3 b99f8879 116686848K active/Offline, Failed
/dev/loop1:
Magic : de11de11
Version : 01.00.00
Controller GUID : 4C534920:20202020:53563632:38343632:35370000:20300000
(LSI SV62846257)
Container GUID : 4C534920:20202020:1000005B:10009269:4974DEC4:0689B9A9
(LSI 01/19/19 14:12:52)
Seq : 0000000b
Redundant hdr : yes
Virtual Disks : 1
VD GUID[0] : 4C534920:20202020:1000005B:10009269:48421933:6EAADB6C
(LSI 05/31/18 22:36:19)
unit[0] : 0
state[0] : Degraded, Consistent
init state[0] : Not Initialised
access[0] : Read/Write
Name[0] :
Raid Devices[0] : 4 (0@0K 1@0K 2@0K --@0K)
Chunk Size[0] : 1024 sectors
Raid Level[0] : RAID5
Device Size[0] : 116686848
Array Size[0] : 350060544
Physical Disks : 255
Number RefNo Size Device Type/State
0 b99f8876 116686848K active/Online
1 b99f8877 116686848K /dev/loop1 active/Online
2 b99f8878 116686848K active/Online
3 b99f8879 116686848K active/Offline, Failed
/dev/loop2:
Magic : de11de11
Version : 01.00.00
Controller GUID : 4C534920:20202020:53563632:38343632:35370000:20300000
(LSI SV62846257)
Container GUID : 4C534920:20202020:1000005B:10009269:4974DEC4:0689B9A9
(LSI 01/19/19 14:12:52)
Seq : 0000000b
Redundant hdr : yes
Virtual Disks : 1
VD GUID[0] : 4C534920:20202020:1000005B:10009269:48421933:6EAADB6C
(LSI 05/31/18 22:36:19)
unit[0] : 0
state[0] : Degraded, Consistent
init state[0] : Not Initialised
access[0] : Read/Write
Name[0] :
Raid Devices[0] : 4 (0@0K 1@0K 2@0K --@0K)
Chunk Size[0] : 1024 sectors
Raid Level[0] : RAID5
Device Size[0] : 116686848
Array Size[0] : 350060544
Physical Disks : 255
Number RefNo Size Device Type/State
0 b99f8876 116686848K active/Online
1 b99f8877 116686848K active/Online
2 b99f8878 116686848K /dev/loop2 active/Online
3 b99f8879 116686848K active/Offline, Failed
The regular files look much the same:
RAID-Server:/RAID/Server-Main/Temp# mdadm -E
/RAID/Server-Main/Temp/LSI-RAID1
/RAID/Server-Main/Temp/LSI-RAID1:
Magic : de11de11
Version : 01.00.00
Controller GUID : 4C534920:20202020:53563632:38343632:35370000:20300000
(LSI SV62846257)
Container GUID : 4C534920:20202020:1000005B:10009269:4974DEC4:0689B9A9
(LSI 01/19/19 14:12:52)
Seq : 0000000b
Redundant hdr : yes
Virtual Disks : 1
VD GUID[0] : 4C534920:20202020:1000005B:10009269:48421933:6EAADB6C
(LSI 05/31/18 22:36:19)
unit[0] : 0
state[0] : Degraded, Consistent
init state[0] : Not Initialised
access[0] : Read/Write
Name[0] :
Raid Devices[0] : 4 (0@0K 1@0K 2@0K --@0K)
Chunk Size[0] : 1024 sectors
Raid Level[0] : RAID5
Device Size[0] : 116686848
Array Size[0] : 350060544
Physical Disks : 255
Number RefNo Size Device Type/State
0 b99f8876 116686848K active/Online
1 b99f8877 116686848K active/Online
2 b99f8878 116686848K active/Online
3 b99f8879 116686848K active/Offline, Failed
Physical disks not in metadata!:
b99f8876 -unknown-
Does anyone have any advice? I suspect I will have to force the
creation of an array, manually inputting the array parameters - assuming
it can be made to work at all. I have multiple backups of the drive
images, so I can fiddle all I want.
