superblock corrupt

[practice]

$ sudo dumpe2fs /dev/sda2 | grep "Block size"
dumpe2fs 1.44.1 (24-Mar-2018)
Block size:               4096
shawn@mars:~$ sudo fsck /dev/mapper/vgstack-lvroot
fsck from util-linux 2.31.1
e2fsck 1.44.1 (24-Mar-2018)
fsck.ext4: Input/output error while trying to open /dev/mapper/vgstack-lvroot

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
 or
    e2fsck -b 32768 <device>

shawn@mars:~$ man mke2fs
shawn@mars:~$ sudo mke2fs -n /dev/mapper/vgstack-lvroot
mke2fs 1.44.1 (24-Mar-2018)
Creating filesystem with 457421824 4k blocks and 114360320 inodes
Filesystem UUID: ca2c41b4-050a-4b76-9547-757450c70e60
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848

shawn@mars:~$ sudo e2fsck -b 32768 /dev/mapper/vgstack-lvroot
e2fsck 1.44.1 (24-Mar-2018)
e2fsck: Input/output error while trying to open /dev/mapper/vgstack-lvroot

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem.  If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>
 or
    e2fsck -b 32768 <device>

흠... sdb 디스크가 사라져서 그런가...