#!/bin/bash
# For AWS EC2 CentOS boxes that use LVM and have storage volumes presented as /dev/xvd_ (where _ is a letter).

main() {
  local devPrefix=xvd ;
  local dev=$1 ;
  local gb=$2 ;
  local fs_dir=$3 ;
  local vg=$4 ;
  local lv_name=$5 ;
  [[ $dev ]]     || { echo "ERROR: Must have first argument, the device letter (like 'b' for /dev/xvdb)'." ; exit 1 ; } ;
  [[ $gb ]]      || { echo "ERROR: Must have second argument, the size in GB." ; exit 1 ; } ;
  [[ $fs_dir ]]  || { echo "ERROR: Must have third argument, the filesystem directory (like /var or /var/log)." ; exit 1 ; } ;
  [[ $vg ]]      || { echo "ERROR: Must have fourth argument, the volume group." ; exit 1 ; } ;
  [[ $lv_name ]] || { echo "ERROR: Must have fifth argument, the logical volume name." ; exit 1 ; } ;
  df -h | grep $fs_dir
  pvs | grep $devPrefix$dev || pvcreate /dev/$devPrefix$dev
  vgextend $vg /dev/$devPrefix$dev
  lvextend -L+${gb}G /dev/mapper/${vg}-$lv_name && xfs_growfs $fs_dir
  df -h | grep $fs_dir
}

cd $(dirname $0) || { echo "ERROR: $? from 'cd dirname($0)'." ; exit 1 ; } ;
main "$@" || { echo "ERROR: $? from 'main($@)'." ; exit 1 ; } ;

#