[CentOS] Recover from an fsck failure

Fri May 29 13:22:31 UTC 2020
James B. Byrne <byrnejb at harte-lyne.ca>


On Thu, May 28, 2020 19:38, Robert Nichols wrote:

> What output do you get from:
>
>      file -s /dev/mapper/vg_voinet01-lv_log
>      lsblk -f /dev/mapper/vg_voinet01-lv_log
>

file -s /dev/mapper/vg_voinet01-lv_log
/dev/mapper/vg_voinet01-lv_log: symbolic link TO '../DM-5'
dm-f

lsblk -f /dev/mapper/vg_voinet01-lv_log
NAME                      FSTYPE LABEL UUID MOUNTPOINT
vg_voinet01-lv_log (dm-5)


The cloned source is a CentOS-6.6 based FreePBSX appliance using lvm.  It has a
single 500GB HDD.  The source host is running and testing of its HDD shows no
errors from the test.  However, the number of recoverable read and write errors
are abnormally high indicating that the HDD is approaching the end of its
service life. I wish to replace it without having to rebuild the entire PBX
system from scratch.

All of the LVMs on the cloned HDD are ext4 file systems.  The only one that
failed is the log partition /var/log.  If I cannot fix this then I wish to
replace it with an empty fs and simply rsync the contents of /var/log from the
running system to it. I need to do this anyway just prior to replacement as the
PBX is running.

However, it is about six years since I last had to do this and while I have my
notes I would appreciate a short precis of the steps involved.

This is the file system layout.

/etc/fstab
/dev/mapper/vg_voinet01-lv_root             /           ext4  defaults  1 1
UUID=302ab0fo-f985-4903-86e2-e218b1345e0    /boot       ext4  defaults  1 2
/dev/mapper/vg_voinet01-lv_home             /home       ext4  defaults  1 2
/dev/mapper/vg_voinet01-LogVol04            /var        ext4  defaults  1 2
/dev/mapper/vg_voinet01-lv_log              /var/log    ext4  defaults  1 2
/dev/mapper/vg_voinet01-lv_spool            /var/spool  ext4  defaults  1 2
/dev/mapper/vg_voinet01-lv_swap             swap        swap  defaults  0 0
tmpfs                                       /dev/shm    tmpfs defaults,nodev,. . .


parted -l
Model: ATA WDC WD1002FAEX-0 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start    End      Size     Type       File system   Flags
 1     1094kB   525MB    524MB    primary    ext4          boot
 2     525MB    500GB    500GB    primary                  lvm

Model: Linux device-maper (linear) (dm)
Disk: /dev/mapper/vg_voinet01-lv_spool: 68.7GB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number Start    End      Size     Type       File system   Flags
 1     0.00B    68.7GB   68.7GB   primary    ext4

Error: /dev/mapper/vg_voinet01-lv_log: unrecognized disk label

Model: Linux device-maper (linear) (dm)
Disk: /dev/mapper/vg_voinet01-lv_home: 3355MB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number Start    End      Size     Type       File system   Flags
 1     0.00B    3355MB   3355MB   primary    ext4

Model: Linux device-maper (linear) (dm)
Disk: /dev/mapper/vg_voinet01-LogVol04: 336GB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number Start    End      Size     Type       File system   Flags
 1     0.00B    336GB    336GB    primary    ext4


Error: /dev/mapper/vg_voinet01-lv_swap: unrecognized disk label

Model: Linux device-maper (linear) (dm)
Disk: /dev/mapper/vg_voinet01-lv_spool: 67.1GB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number Start    End      Size     Type       File system   Flags
 1     0.00B    67.1GB   67.1GB   primary    ext4

I will have to do this from a live cd I presume as the shell that the failed
boot process dropped me into give a "File-based locking initialisation failed."
when I try to run vgdisplay or vgs.

Any guidance appreciated.

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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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