[SOLVED] I can't mount lvm, i get error message while mounting

maxam · 06-19-2017, 10:34 AM

Code:

I have HDD which installed centos in it,  i wanted to get files from it using Fedora live USB. 
I found some useful posts about it, first time i mount it to /mnt and changed its fstab file, and when i want again mount it, i can't mount it, it returns errors. Above i write all steps which i did.

    [root@localhost ~]# lvdisplay 
    --- Logical volume ---
    LV Path                /dev/vg_dstkpi/lv_root
    LV Name                lv_root
    VG Name                vg_dstkpi
    LV UUID                Sq7sV4-zQsX-0CH3-9HU2-ZTES-A6nI-hvNtfY
    LV Write Access        read/write
    LV Creation host, time dstkpi.dst.uz, 2016-05-14 18:35:10 -0400
    LV Status              available
    # open                 0
    LV Size                50.00 GiB
    Current LE             12800
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           253:0
   
    --- Logical volume ---
    LV Path                /dev/vg_dstkpi/lv_home
    LV Name                lv_home
    VG Name                vg_dstkpi
    LV UUID                5wA6g6-VfJW-g6dW-SZ7P-ncwj-at1h-c098Du
    LV Write Access        read/write
    LV Creation host, time dstkpi.dst.uz, 2016-05-14 18:35:30 -0400
    LV Status              available
    # open                 0
    LV Size                94.71 GiB
    Current LE             24247
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           253:1
   
    --- Logical volume ---
    LV Path                /dev/vg_dstkpi/lv_swap
    LV Name                lv_swap
    VG Name                vg_dstkpi
    LV UUID                aUbOVe-gbEn-LfKH-EQOu-etPN-FyOd-bCuxb3
    LV Write Access        read/write
    LV Creation host, time dstkpi.dst.uz, 2016-05-14 18:36:11 -0400
    LV Status              available
    # open                 2
    LV Size                3.84 GiB
    Current LE             984
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           253:2


 After that i wanted mount it like this:

    [root@localhost ~]# mount /dev/vg_dstkpi/lv_root /mnt/rescue/
    mount: wrong fs type, bad option, bad superblock on /dev/mapper/vg_dstkpi-lv_root,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

I opened log file.

    [root@localhost ~]# dmesg | tail
    [ 2116.827233] ata3.00: configured for UDMA/133
    [ 2116.827249] sd 2:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
    [ 2116.827252] sd 2:0:0:0: [sda] tag#0 Sense Key : Medium Error [current] 
    [ 2116.827255] sd 2:0:0:0: [sda] tag#0 Add. Sense: Unrecovered read error - auto reallocate failed
    [ 2116.827258] sd 2:0:0:0: [sda] tag#0 CDB: Read(10) 28 00 00 0f b0 08 00 00 08 00
    [ 2116.827260] blk_update_request: I/O error, dev sda, sector 1028104
    [ 2116.827278] EXT4-fs (dm-0): can't read group descriptor 0
    [ 2116.827298] ata3: EH complete
    [ 2116.833657] EXT4-fs (dm-0): couldn't mount as ext3 due to feature incompatibilities
    [ 2116.833954] EXT4-fs (dm-0): couldn't mount as ext2 due to feature incompatibilities



**Here are images from disks utility:**
https://i.stack.imgur.com/jXKTi.png

**it's /dev/vg_dstkpi/lv_root:**
 https://i.stack.imgur.com/VrIpn.png

MensaWater · 06-19-2017, 12:31 PM

The messages suggest it tried first as ext2 then as ext3 and MAYBE as ext4.

You don't say what kind of filesystem was on the original. Was it one of those? Or was it maybe something else like xfs? gfs? What version of CentOS was this on originally? In CentOS7 I think xfs was the default.

Also you don't say what version of Fedora live you're using.

rknichols · 06-19-2017, 12:54 PM

Your disk has at least one bad sector, and that one is in the first ext4 group descriptor block, preventing the mount from succeeding.

Suggested procedure:

Use ddrescue to salvage as much data as possible from /dev/vg_dstkpi/lv_root to another disk partition or LV of at least 50GiB (53.7GB) in size.
See if fsck can repair the filesystem on that copy.
If the repair was successful and the files appear intact, use dd to restore the copy back to the original LV. That writing should cause the drive to reallocate any bad sectors in that LV.
Run "smartctl -A" on the drive to evaluate its overall health.

B-RAH · 06-27-2017, 02:34 PM

Run fsck to repair (like rknichols said), then blkid to find the fstype. I would edit /etc/fstab (/dev/vg_dstkpi/lv_root /mnt/rescue/ {fstype} defaults 0 0), then run umount -a then mount -a