#lvscan

[rm-minus-rf]

mount: unknown filesystem type 'LVM2_member'

disk errors or file systems errors are what we sysadmins dread the most.  my most recent encounter of one taught me a thing or two:

# lvmdiskscan

# lvdisplay

if you tried to mount the disk using its VG name it might give you the following error:

"mount: special device /dev/[vg_name]/[lv_name] does not exist"

and if you did an:

# lvscan

it might show you that the disk is "inactive", so all you need to do now is make it active!

# modprobe dm-mod

# vgchange -ay

doing another lvscan now should label your disk now as "ACTIVE", so then go ahead now and mount it!