configure-btrfs-compression

#!/bin/bash

# enable/disable compression for btrfs
# THIS IS NOT TESTED FOR EVERY POSSIBLE CASE OF /etc/fstab
# USE WITH CARE (maybe backup /etc/fstab before running it)
#
# you might want to convert old ext2/3/4 file systems to btrfs
# see https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-convert
#
# btrfs fi defragment -r -clzo .   # compress existing data
#
# install btrfs-compsize to see performance

with=`grep -v "^#" /etc/fstab |grep btrfs |grep compress`
without=`grep -v "^#" /etc/fstab |grep btrfs |grep -v compress`

case $1 in
    status)
	# list btrfs filesystems
	echo BTRFS FILESYSTEMS WITH COMPRESSION
	echo "$with"
	echo
	# check if it already has compress option
	#cat /etc/fstab |grep -v ^# |grep btrfs |grep -v compress
	echo BTRFS FILESYSTEMS WITHOUT COMPRESSION
	echo "$without"
    ;;
    start|enable)
	echo ENABLING BTRFS COMPRESSION
	grep "compress=lzo" /etc/fstab &>/dev/null || sed -i "s/btrfs.*defaults/\0,compress=lzo/g" /etc/fstab
	#mount -o remount,rw mountpoint
    ;;
    remount)
	echo REMOUNTING ALL BTRFS FILESYSTEMS
	grep -v "^#" /etc/fstab  |grep btrfs |awk '{print $1}' | while read a; do mount -o remount $a; done
    ;;
    stop|disable)
	echo DISABLING BTRFS COMPRESSION
	grep "compress=lzo" /etc/fstab &>/dev/null && sed -i "s/,compress=lzo//g" /etc/fstab
	#mount -o remount,rw mountpoint
    ;;
    *)
	echo "Syntax: $0 [status|start|enable|stop|disable|remount]"
    ;;
esac