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I recently upgraded my OS from RHEL 5 to 6. To do so, I installed the new OS on new disks, and I want to mount the old disks. The old disks are listed as /dev/sdc and sdd in the new system, they were created as a RAID 1 array using LVM, using the default setup from the RHEL install GUI.

I managed to mount the old disks and use them for the last two weeks, but after a reboot, they did not remount, and I can't figure out what to do to get them back on line. I have no reason to believe there is anything wrong with the disks.

(I'm in the process of doing dd copy of the disks, I have an older backup, but I hope I don't have to use either of these...)

Using fdisk -l :

# fdisk -l

Disk /dev/sdb: 300.1 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00042e35

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1       30596   245760000   fd  Linux raid autodetect
/dev/sdb2           30596       31118     4194304   fd  Linux raid autodetect
/dev/sdb3           31118       36482    43080704   fd  Linux raid autodetect

Disk /dev/sda: 300.1 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00091208

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       30596   245760000   fd  Linux raid autodetect
/dev/sda2           30596       31118     4194304   fd  Linux raid autodetect
/dev/sda3           31118       36482    43080704   fd  Linux raid autodetect

Disk /dev/sdc: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00038b0e

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       77825   625129281   fd  Linux raid autodetect

Disk /dev/sdd: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00038b0e

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1       77825   625129281   fd  Linux raid autodetect

Disk /dev/md2: 4292 MB, 4292804608 bytes
2 heads, 4 sectors/track, 1048048 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/md1: 251.7 GB, 251658043392 bytes
2 heads, 4 sectors/track, 61439952 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/md127: 44.1 GB, 44080955392 bytes
2 heads, 4 sectors/track, 10761952 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

And then

# mdadm --examine /dev/sd[cd]
mdadm: /dev/sdc is not attached to Intel(R) RAID controller.
mdadm: /dev/sdc is not attached to Intel(R) RAID controller.
/dev/sdc:
          Magic : Intel Raid ISM Cfg Sig.
        Version : 1.1.00
    Orig Family : 8e7b2bbf
         Family : 8e7b2bbf
     Generation : 0000000d
     Attributes : All supported
           UUID : c8c81af9:952cedd5:e87cafb9:ac06bc40
       Checksum : 014eeac2 correct
    MPB Sectors : 1
          Disks : 2
   RAID Devices : 1

  Disk01 Serial : WD-WCASY6849672
          State : active
             Id : 00010000
    Usable Size : 1250259208 (596.17 GiB 640.13 GB)

[Volume0]:
           UUID : 03c5fad1:93722f95:ff844c3e:d7ed85f5
     RAID Level : 1
        Members : 2
          Slots : [UU]
    Failed disk : none
      This Slot : 1
     Array Size : 1250258944 (596.17 GiB 640.13 GB)
   Per Dev Size : 1250259208 (596.17 GiB 640.13 GB)
  Sector Offset : 0
    Num Stripes : 4883824
     Chunk Size : 64 KiB
       Reserved : 0
  Migrate State : idle
      Map State : uninitialized
    Dirty State : clean

  Disk00 Serial : WD-WCASY7183713
          State : active
             Id : 00000000
    Usable Size : 1250259208 (596.17 GiB 640.13 GB)
mdadm: /dev/sdd is not attached to Intel(R) RAID controller.
mdadm: /dev/sdd is not attached to Intel(R) RAID controller.
/dev/sdd:
          Magic : Intel Raid ISM Cfg Sig.
        Version : 1.1.00
    Orig Family : 8e7b2bbf
         Family : 8e7b2bbf
     Generation : 0000000d
     Attributes : All supported
           UUID : c8c81af9:952cedd5:e87cafb9:ac06bc40
       Checksum : 014eeac2 correct
    MPB Sectors : 1
          Disks : 2
   RAID Devices : 1

  Disk00 Serial : WD-WCASY7183713
          State : active
             Id : 00000000
    Usable Size : 1250259208 (596.17 GiB 640.13 GB)

[Volume0]:
           UUID : 03c5fad1:93722f95:ff844c3e:d7ed85f5
     RAID Level : 1
        Members : 2
          Slots : [UU]
    Failed disk : none
      This Slot : 0
     Array Size : 1250258944 (596.17 GiB 640.13 GB)
   Per Dev Size : 1250259208 (596.17 GiB 640.13 GB)
  Sector Offset : 0
    Num Stripes : 4883824
     Chunk Size : 64 KiB
       Reserved : 0
  Migrate State : idle
      Map State : uninitialized
    Dirty State : clean

  Disk01 Serial : WD-WCASY6849672
          State : active
             Id : 00010000
    Usable Size : 1250259208 (596.17 GiB 640.13 GB)

Trying to assemble:

# mdadm --assemble /dev/md3 /dev/sd[cd]
mdadm: no RAID superblock on /dev/sdc
mdadm: /dev/sdc has no superblock - assembly aborted

I've tried:

# mdadm --examine --scan /dev/sd[cd]
ARRAY metadata=imsm UUID=c8c81af9:952cedd5:e87cafb9:ac06bc40
ARRAY /dev/md/Volume0 container=c8c81af9:952cedd5:e87cafb9:ac06bc40 member=0 UUID=03c5fad1:93722f95:ff844c3e:d7ed85f5

And adding this to the /etc/mdadm.conf file, but it doesn't seem to help. I'm not sure what to try next. Any help would appreciated.

EDIT 1: Does "Magic : Intel Raid ISM Cfg Sig." indicate that I need to use dmraid?

EDIT 2: As suggested below, I tried dmraid, but I don't know what the response means:

# dmraid -ay
RAID set "isw_cdjaedghjj_Volume0" already active
device "isw_cdjaedghjj_Volume0" is now registered with dmeventd for monitoring
RAID set "isw_cdjaedghjj_Volume0p1" already active
RAID set "isw_cdjaedghjj_Volume0p1" was not activated

EDIT 2b: So, now I can see something here:

# ls /dev/mapper/
control  isw_cdjaedghjj_Volume0  isw_cdjaedghjj_Volume0p1

but it doesn't mount:

# mount /dev/mapper/isw_cdjaedghjj_Volume0p1 /mnt/herbert_olddrive/
mount: unknown filesystem type 'linux_raid_member'

EDIT 2c: Ok, maybe this might help:

# mdadm -I /dev/mapper/isw_cdjaedghjj_Volume0
mdadm: cannot open /dev/mapper/isw_cdjaedghjj_Volume0: Device or resource busy.

# mdadm -I /dev/mapper/isw_cdjaedghjj_Volume0p1
#

The second command returns nothing. Does this mean anything or am I way off track?

EDIT 3: /proc/mdstat:

# cat /proc/mdstat
Personalities : [raid1]
md127 : active raid1 sda3[1] sdb3[0]
      43047808 blocks super 1.1 [2/2] [UU]
      bitmap: 0/1 pages [0KB], 65536KB chunk

md1 : active raid1 sda1[1]
      245759808 blocks super 1.0 [2/1] [_U]
      bitmap: 2/2 pages [8KB], 65536KB chunk

md2 : active raid1 sda2[1]
      4192192 blocks super 1.1 [2/1] [_U]

unused devices: <none>

md1 and md2 are raid arrays on sda and sdb, which are used by the new OS.

share|improve this question
    
Have you tried mdadm --assemble /dev/md3 /dev/sd[cd]1? Also, could you edit into your question the output of cat /proc/mdstat - that md127 looks like it might be the right thing already. –  MadHatter Jul 8 at 11:19
    
Yes: the message is mdadm: cannot open device /dev/sd[cd]1: No such file or directory –  RD Miles Jul 8 at 11:21
    
Also tried the same thing using sd[cd] without the 1, and get: mdadm: no RAID superblock on /dev/sdc –  RD Miles Jul 8 at 11:23
    
That's weird, because you've shown us those partitions. Could you try it without the glob, just do mdadm --assemble /dev/md3 /dev/sdc1 /dev/sdd1? Also, still waiting for the cat /proc/mdstat. –  MadHatter Jul 8 at 11:27
    
Same response: mdadm: cannot open device /dev/sdc1: No such file or directory... I don't really understand what Volume0 means in the --examine output: I think it indicates that there is a VolumeGroup, but I'm not sure how to set it up. –  RD Miles Jul 8 at 11:34

2 Answers 2

A bit confused here - is it mdadm raid or lvm raid? In the question you mention lvm raid, yet keep trying to use mdadm raid.

for lvm - first use

pvscan -u

possibly

pvscan -a --cache /dev/sdc /dev/sdd

would be enough to recreate your device. if not, use

vgchange -ay VolGroup00

or

vgcfgrestore VolGroup00

The other possibility is that you used dmraid - can you try

dmraid -ay

but the disks must be connected to the intel fakeraid controller (make sure raid is enabled in bios for the ata slots the disks are connected to)

share|improve this answer
    
I believe it is a LVM over a RAID1... but I could be wrong. pvscan -u UUID produces no results, nor do the subsequent suggestions. Do I need to rebuild the physical volumes from scratch? –  RD Miles Jul 8 at 1:37
    
Using vgscan -vvvv, I find this phrase "#filters/filter-partitioned.c:45 /dev/sdd: Skipping: Partition table signature found" ... does this help? Should I delete the partition table? –  RD Miles Jul 8 at 2:08
    
Quite possibly you had a dmraid setup using the bios "raid" capability. –  Dani_l Jul 8 at 5:19
    
I added the output from dmraid -ay, @Dani_l, can you make sense of it? –  RD Miles Jul 8 at 11:44
    
looks like dmraid is catching the already active sd[ab] devices. A stupid question - what's the result of mdadm -I /dev/md/Volume0 ? That's a capital i, btw, not lowercase L –  Dani_l Jul 8 at 15:26
up vote 0 down vote accepted

It appears that I had a conflict between the dmraid setup and the mdadm setup. I don't understand the details, but what I finally did to fix it was stop the dmraid

dmraid -an

and then assemble the drives to a whole new md device:

mdadm --assemble /dev/md4 /dev/sdc /dev/sdd

When I did this, /dev/md126 and /dev/md126p1 mysteriously appeared (mysterious to me, but I'm sure someone can explain it), and I mounted md126p1:

mount /dev/md126p1 /mnt/olddrive

And voilà: my data reappeared! There were a couple of corrupted files, but no data loss.

Thank you @Dani_l and @MadHatter for your help!

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