LVM: Mount LVM Partition(s) in Rescue Mode -

LVM: Mount LVM Partition(s) in Rescue Mode

# When system is not able to boot up due to OS problems we may be leaded to boot it into
# Rescue Mode using a installation CD.

# While booting in this mode, system will try to find out linux installation and mount it
# under /mnt/sysimage giving us the opportunity of getting to F.S. in order to make
# appropriate modifications for system to be recovered. Sometimes, if OS is seriously
# damaged this is not possible. In this case, it may be useful to manually mount LVM
# partitions to check/modify OS to recover server.

# Boot the machine with installation CD into Rescue Mode.

sh-3.2# df -k
   Filesystem                1K-blocks        Used     Available Use%   Mounted on
   /dev                         517568           0        517568    0%   /dev
   /tmp/loop0                   109184      109184             0 100%   /mnt/runtime

sh-3.2# vgs
   sh: vgs: command not found

sh-3.2# pvscan
   sh: pvscan: command not found

# We get this kind of errors because lvm commands are not available in Rescue Mode.
# Instead we will precede any lvm commands by "lvm" command this way:

sh-3.2# lvm vgs
   VG    #PV #LV #SN Attr      VSize    VFree
   vg00    1    7    0 wz--n-    31.50G      0

# Now we are ready to use lvm commands so we can mount our lvm volumes

# Check existing logical volumes

sh-3.2# lvm lvs
   LV      VG    Attr    LSize Origin Snap% Move Log Copy% Convert
   lvhome vg00 -wi--- 4.50G
   lvopt   vg00 -wi--- 5.00G
   lvroot vg00 -wi--- 5.00G
   lvswap vg00 -wi--- 5.00G
   lvtmp   vg00 -wi--- 2.00G
   lvusr   vg00 -wi--- 5.00G
   lvvar   vg00 -wi--- 5.00G

# Activate our root volume group

sh-3.2# lvm vgchange -a y vg00
7 logical volume(s) in volume group "vg00" now active

# Mount any desired volume, in this case "/" filesystem

sh-3.2# mkdir /mnt/temp
sh-3.2# mount /dev/vg00/lvroot /mnt/temp

# Now we are able to access our OS data to make any needed check/modification