[linux-lvm] LVM issues after replacing linux mdadm RAID5 drive

[L.M.J]

What do you think about this command :


  ~# dd if=/dev/md0 bs=512 count=255 skip=1 of=/tmp/md0.txt
   
	[..]
	physical_volumes {
		pv0 {
			id = "5DZit9-6o5V-a1vu-1D1q-fnc0-syEj-kVwAnW"
			device = "/dev/md0"
			status = ["ALLOCATABLE"]
			flags = []
			dev_size = 7814047360
			pe_start = 384
			pe_count = 953863
		}
	}
	logical_volumes {

		lvdata {
			id = "JiwAjc-qkvI-58Ru-RO8n-r63Z-ll3E-SJazO7"
			status = ["READ", "WRITE", "VISIBLE"]
			flags = []
			segment_count = 1
	[..]

I presume I still have data on my broken RAID5.

I did a pvcreate --restorefile and vgcfgrestore.
I can see now my 2 LVM, but my EXT4 filesystem are empty, df reports some realist disk usage, fsck (Read
only) find tons of errors.

Is there a way to recover my data on the EXT4 FS ?




Le Fri, 18 Apr 2014 23:14:17 +0200,
"L.M.J" <linuxmasterjedi at free.fr> a écrit :

> Le Thu, 17 Apr 2014 15:33:48 -0400,
> Stuart Gathman <stuart at gathman.org> a écrit :
> 
> Thanks for your answer
> 
> > Fortunately, your fsck was read only.  At this point, you need to 
> > crash/halt your system with no shutdown (to avoid further writes to the 
> > mounted filesystems).
> > Then REMOVE the new drive.  Start up again, and add the new drive properly.
> 
> RAID5 recreate : started with 2 original drives
> 
> ~# mdadm --assemble --force /dev/md0 /dev/sdc1 /dev/sdd1
> 
> md0 status is normal, missing new drive : sdb(1)
> ~# cat /proc/mdstat 
> md0 : active raid5 sdc1[0] sdd1[1]
>       3907023872 blocks level 5, 64k chunk, algorithm 2 [3/2] [UU_]
> 
> 
> > You should check stuff out READ ONLY.  You will need fsck (READ ONLY at 
> > first), and at least some data has been destroyed.
> > If the data is really important, you need to copy the two old drives 
> > somewhere before you do ANYTHING else.  Buy two more drives!  That will 
> > let you recover from any more mistakes typing Create instead of Assemble 
> > or Manage.  (Note that --assume-clean warns you that you really need to 
> > know what you are doing!)
> 
> I try a read-only fsck
> 
> ~# fsck -n -v -f /dev/lvm-raid/lvmp3 
> fsck from util-linux-ng 2.17.2
> e2fsck 1.41.11 (14-Mar-2010)
> Resize inode not valid.  Recreate? no
> Pass 1: Checking inodes, blocks, and sizes
> Inode 7, i_blocks is 114136, should be 8.  Fix? no
> Inode 786433 is in use, but has dtime set.  Fix? no
> Inode 786433 has imagic flag set.  Clear? no
> Inode 786433 has compression flag set on filesystem without compression
> support.  Clear? no Inode 786433 has INDEX_FL flag set but is not a directory.
> Clear HTree index? no
> HTREE directory inode 786433 has an invalid root node.
> Clear HTree index? no
> Inode 786433, i_blocks is 4294967295, should be 0.  Fix? no
> [...]
> Directory entry for '.' in ... (11) is big.
> Split? no
> Missing '.' in directory inode 262145.
> Fix? no
> Invalid inode number for '.' in directory inode 262145.
> Fix? no
> Directory entry for '.' in ... (262145) is big.
> Split? no
> Directory inode 917506, block #0, offset 0: directory corrupted
> Salvage? no
> e2fsck: aborted
> 
> 
> Sounds bad, what should I do know ?
> 
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