lvextend -L+10G /dev/system-zjrak/assets
e2fsck -f /dev/system-zjrak/assets
resize2fs /dev/system-zjrak/assets

• use rescue mode and select ubuntu 14.04
• connect and use sudo
• find the volume group using lvscan (exemple : /dev/system-uwslj/root)
• check the disk with

  e2fsck -fy /dev/system-uwslj/root

• resize the disk to 4G (only 2G are used by default)

  resize2fs /dev/system-uwslj/root 4G

• reduce the lvm volume

  lvreduce -L 5G /dev/system-uwslj/root

• resize the partition with the empty space

  resize2fs /dev/system-uwslj/root

• disconnect from the rescue mode and restart in normal mode

• got to “Datacenter” then “Storage”
• add a “lvm” volume and select the group