Need hlep with LVM -

[David Beveridge]

If I understand you correctly you will need to do something along these lines...
You need to know the names of your volume groups and logical volumes.

use pvscan, vgscan & lvscan to display what you have. eg
root at MythTV:/etc# pvscan
  PV /dev/sdc2   VG vg_tv   lvm2 [1.82 TiB / 59.31 GiB free]
  Total: 1 [1.82 TiB] / in use: 1 [1.82 TiB] / in no VG: 0 [0   ]
root at MythTV:/etc# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "vg_tv" using metadata type lvm2
root at MythTV:/etc# lvscan
  ACTIVE            '/dev/vg_tv/lv_photo' [292.97 GiB] inherit
  ACTIVE            '/dev/vg_tv/lv_music' [195.31 GiB] inherit
  ACTIVE            '/dev/vg_tv/lv_video' [1.19 TiB] inherit
  ACTIVE            '/dev/vg_tv/lv_backup' [97.66 GiB] inherit


ensure that /dev/sdb5 is partition type LVM

# fdisk /dev/sdb
use p command to display partitions
use t command to change type to 8e

Add the partition to you volume group

# pvcreate /dev/sdb5

Add the new partition to your volume group

# vgextend vg_name /dev/sdb5

Extend the root logical volume

# lvextend -l +100%FREE /dev/vg_name/lv_root /dev/sdb5

Resize the volume to match

# resize2fs /dev/vg_name/lv_root