Re: Bug#597563: grub-common: grub-probe segfaults scanning lvm devices

On 01/08/2011 11:53 PM, Matthew Gabeler-Lee wrote:

On Sat, 8 Jan 2011, Vladimir 'φ-coder/phcoder' Serbinenko wrote:

quoted

As was recommended I forward the remaining part to linux-raid mailing
list.
In short: on his system mdraid, raid5, 4 devices, metadata (presumably)
0.90, two devices have index 0.
If such situation is valid please advice me on how such situation should
be handled.
@Matthew: could you supply mdadm -Q outputput and *last* 64K of every
disk?

Sorry, I've noticed that I've looked into the wrong place all the long.
md2 is fine. I suppose it's a problem with md0 (all mdraid are assembled
at the beginning). Since md0 is raid1, its misassembly wouldn't have any
influence (we don't write to devices). mdstat lists both md0 and md1 as
having no duplicate indices. I would need info on md0 for this (now
minor) remaining bug.

$ sudo mdadm -QD /dev/md2
/dev/md2:
        Version : 0.90
  Creation Time : Mon Mar 27 14:04:18 2006
     Raid Level : raid5
     Array Size : 2185667136 (2084.41 GiB 2238.12 GB)
  Used Dev Size : 728555712 (694.80 GiB 746.04 GB)
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Sat Jan  8 17:40:20 2011
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 01e2f978:88d1f867:34e1e46c:f3c01470
         Events : 0.32040050

    Number   Major   Minor   RaidDevice State
       0       8       35        0      active sync   /dev/sdc3
       1       8       19        1      active sync   /dev/sdb3
       2       8        3        2      active sync   /dev/sda3
       3       8       51        3      active sync   /dev/sdd3

The actual last 64k of all the partitions in the array is all zeros.
So is the 64k up to the end of the "Used Dev Size".  What has some
data in it is the 64k after that.  I hope that has the superblock data
I presume you're looking for.  I.e.  dd if=/dev/sdX3 bs=1024
skip=728555712 count=64.

-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko