After a server crash or due to a human error, volume group device files are not seen under /dev directory. The device files were removed from the filesystem after the system crash, probably due to a filesystem corruption.
# cd /dev # ls vg01 ls: cannot access vg01: No such file or directory
If you check the output of lvdisplay command you would see the vg intact and without any error.
# lvdisplay --- Logical volume --- LV Path /dev/vg01/lv01 LV Name lv01 VG Name vg01 LV UUID iP1MbY-LPMY-nmym-iY2B-CCRJ-ElVY-5L1mql LV Write Access read/write LV Creation host, time localhost.localdomain, 2017-10-11 21:39:45 +0530 LV Status not available # open 1 LV Size 10.00 GiB Current LE 2560 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:3
Creating LVM devices
1. The command vgcfgrestore would fail if you try to recover the volume group using the backup.
# vgcfgrestore -f /etc/lvm/backup/vg01 /dev/sdc 2ba3ce899000-2ba3ce89a000 rw-p 2ba3ce899000 00:00 0 2ba3ce8a5000-2ba3ce8aa000 rw-p 2ba3ce8a5000 00:00 0 2ba3ce8aa000-2ba3d1e83000 r--p 00000000 fd:00 77807 /usr/lib/locale/locale-archive 7fff26a43000-7fff26a58000 rw-p 7ffffffea000 00:00 0 [stack] ffffffffff600000-ffffffffffe00000 ---p 00000000 00:00 0 [vdso] Aborted
2. In order to recreate the LVM devices under /dev/ you will have to use the vgmknodes command. Use the vgmknodes command with verbose options :
# vgmknodes -vv