Unknown Filesystem Type: LVM2_member

Sometimes you can get errors when you try to mount an LVM partition. You can use one of the following two commands to ensure that the disk/partition is present:

# fdisk -l

or

# lvmdiskscan

If you tried to mount the volume by name instead you'll probably also see an error indicating that the device doesn't exist:

# mount /dev/<vol_grp>/<log_vol> /mnt/
mount: special device /dev/<vol_grp>/<log_vol> does not exist

To correct this you can load the dm-mod kernel module and adjust the attributes of the volume group:

# modprobe dm-mod
# vgchange -ay

A quick scan will show that the device should now be available for mounting:

# lvscan