Need help to recover root filesystem after a power supply issue

[Andrey Zhunev <a-j@a-j.ru>]

Hello All,

I am struggling to recover my system after a PSU failure.

One of the hard drives throws some read errors, and that happen to be
my root drive...
My system is CentOS 7, and the root partition is a part of LVM.

[root@mgmt ~]# lvscan
  ACTIVE            '/dev/centos/root' [<98.83 GiB] inherit
  ACTIVE            '/dev/centos/home' [<638.31 GiB] inherit
  ACTIVE            '/dev/centos/swap' [<7.52 GiB] inherit
[root@mgmt ~]#

[root@tftp ~]# file -s /dev/centos/root
/dev/centos/root: symbolic link to `../dm-3'
[root@tftp ~]# file -s /dev/centos/home
/dev/centos/home: symbolic link to `../dm-4'
[root@tftp ~]# file -s /dev/dm-3
/dev/dm-3: SGI XFS filesystem data (blksz 4096, inosz 256, v2 dirs)
[root@tftp ~]# file -s /dev/dm-4
/dev/dm-4: SGI XFS filesystem data (blksz 4096, inosz 256, v2 dirs)


[root@tftp ~]# xfs_repair /dev/centos/root
Phase 1 - find and verify superblock...
superblock read failed, offset 53057945600, size 131072, ag 2, rval -1

fatal error -- Input/output error
[root@tftp ~]#


smartctl shows some pending sectors on /dev/sda, and no reallocated
sectors (yet?).

Can someone please give me a hand to bring root partition back to life
(ideally)? Or, at least, recover a couple of critical configuration
files...


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Best regards,
 Andrey