Terry : Btrfs Compression and Defragmentation

This page last changed on Nov 27, 2012 by terry.

Use case: use Btrfs compression for external HDD

Create Btrfs file system and enable LZO

Depeding on how you would like to make use of Btrfs features:

  • use the external USB HDD as 1 single partition (block device)
  • create 2 partitions (2 block devices) and form a raid1 or raid0 for data (-d), metadata is replicated on all devices by default, unless you manually specify by using -m

Example

mktfs.btrfs /dev/sdd

Enable LZO Compression

Make use of the compression by adding the option when mounting

sudo mount -o compress=lzo /dev/sdd /mnt/btrfs

Btrfs is flexible, LZO compression can be enabled on a subvolume basis

Create a subvolume named subvol1

btrfs subvolume create /mnt/btrfs/subvol1

OR

btrfs subvol create /mnt/btrfs/subvol1

Mount the subvolume and enable compression

mount -t btrfs -o compress=lzo,subvol=subvol1 /dev/sdd /mnt/subvol1

NOTE:

Icon

You can add compression to existing Btrfs file systems at any time, just add the option when mounting and do a defragment to apply compressions to existing data.

Defragment

Defragment can be done to files or directories.

Files

btrfs filesystem defrag file1 file2

Folders

btrfs filesystem defragment /btrfs/junk /btrfs/rubbish

 

Reference

Compression and Defragmentation

http://www.funtoo.org/wiki/BTRFS_Fun

http://docs.oracle.com/cd/E37670_01/E37355/html/ol_btrfs.html

How I Use the Advanced Capabilities of Btrfs