Missing Metadata
Scenario
So after a new install onto a new disk, somehow the original Volume Group Metadata was lost. There was no record of the Volume group with any of the vg or pv commands. As this was a new install there was also no record of any backups in /etc/lvm/backup.
Finding the metadata backup from the physical volume
- Find out where the metadata backup resides on disk (offset=4096)
TechOps1:/home/gbrown # pvck -d -v /dev/sda1 Scanning /dev/sda1 Found label on /dev/sda1, sector 1, type=LVM2 001 Found text metadata area: offset=4096, size=192512 - hex dump the data from the partition
hex -s 4096 /dev/sda1 |sed -e 's/^.\{56\}//g'|head -1500 > hexDump.txtthis removes all of the unnecessary hex and just leaves the stuff we need - reformat the data
- open the output file in a text editor and format it to look the same as one of the backups of the current system in /etc/lvm/backup/ or /etc/lvm/archive/ (if there isn’t any run vgcfgbackup)
- restore using the newly created backup file
TechOps1:/home/gbrown # vgcfgrestore -f hexDumpModified.txt -v system Restored volume group system
- Import and activate the Volume Group
TechOps1:/home/gbrown # vgimport system Volume group "system" successfully imported TechOps1:/home/gbrown # vgchange -ay 4 logical volume(s) in volume group "TechOps1" now active 4 logical volume(s) in volume group "system" now active
- Mount a volume
TechOps1:/home/gbrown # mount /dev/system/root /mnt/ TechOps1:/home/gbrown # ls !$ ls /mnt/ bin .config etc lib lost+found mnt proc root selinux sys usr boot dev home lib64 media opt readme.txt sbin srv tmp var