2

I've finally managed to assemble my RAID10 array again. I'm hoping there might now be a way through this. (There is history, if anyone is interested).

I'm now getting:

# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md127 : active raid10 sdb[0] sde[3] sdc[1]
  5860270080 blocks super 1.2 512K chunks 2 near-copies [4/3] [UU_U]

Now if I try and mount it:

# mount -r -t ext4 /dev/md127 /media/raid2
mount: wrong fs type, bad option, bad superblock on /dev/md127,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

If I check fstab the array ID is different to what mdadm is reporting - so I have tried editing fstab thus:

#UUID=9f6dfcc1-77c1-449a-9fa0-472df354a7b6 /media/raid2 ext4    defaults    0   1
UUID=3c055999-f299-f081-e35c-b3609e758f88 /media/raid2 ext4    defaults        0       1

I get:

# mount -a
mount: /dev/sdb already mounted or /media/raid2 busy

Can anyone recommend anything? Is there an equivalent to 'assume-clean' when mounting, or something similar that might at least give it its best effort before I scrap the whole lot and cry like a baby?

Community
  • 1
Rog
  • 53
  • 1
  • 4

1 Answers1

1

Looks like you did an mdadm --create on "Creation Time : Thu Jun 11 23:21:12 2015", that could be a problem if you used the wrong parameters. What command line did you use?

Also when the mount fails what is reported by... dmesg | tail

And it's a good idea to check the SMART data on the drives to see if they are healthy.

Don't despair. I often work on failed RAID systems and recovery is usually possible in RAID-10 cases.

S.Haran
  • 101
  • 5
  • This is the command line I used to attempt a create: mdadm --create --assume-clean /dev/md127 -v -l 10 -n 4 /dev/sdb /dev/sdc missing /dev/sde – Rog Jun 14 '15 at 15:15
  • This is dmesg after a failed mount: [170499.955951] EXT4-fs (md127): VFS: Can't find ext4 filesystem [171551.503480] EXT4-fs (md127): VFS: Can't find ext4 filesystem [236702.429769] EXT4-fs (md127): VFS: Can't find ext4 filesystem – Rog Jun 14 '15 at 15:17
  • Well dmesg is not showing any trace of an EXT4 filesystem. And the mdadm --create looks reasonable. So more investigation is needed. Were you able to see the SMART data? The Linux command for that is smartctl. The safest way to proceed would be to take images of each RAID member drive and perform recovery work on the images. I know that's not so easy with 3TB drives. Doing recovery work via forum posts is cumbersome. Are you open to having a chat session to discuss this more? – S.Haran Jun 14 '15 at 21:28
  • I've installed smartmontools (wasn't installed before), and output the info, here: http://pastebin.com/cZkX9pbp - yes, a chat session would be great! What's your preferred chat service? – Rog Jun 15 '15 at 14:11
  • SMART is showing Serial Number: W1F15XME as failing. See the web link in my profile I have a chat service there or we can do google chat. – S.Haran Jun 15 '15 at 18:27