Convert existing ext4 filesystem to btrfs
What I want to achieve is getting btrfs features like snapshots, compression and deduplication The problem is, my system already running and containing data, filesystem is ext4 under linux lvm. So I will convert existing ext4 filesystem to btrfs, keeping lvm partition, and only /home will be converted Converting to btrfs in-place LVM partition: NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 465.8G 0 disk ├─sda1 8:1 0 123M 0 part /boot/efi ├─sda2 8:2 0 390.6G 0 part │ ├─VGVG-Fedora--30--root 253:0 0 60G 0 lvm / │ ├─ VGVG -Archive 253:1 0 25.6G 0 lvm │ └─ VGVG -Home3rd 253:2 0 200G 0 lvm /home First, go to rescue mode and unmount /home , or boot into single-user mode # systemctl rescue # umount /home Fix filesystem issue: # fsck.ext4 -fv /dev/mapper/VGVG-Home3rd When filesystem is clean for error, now convert to btrfs: # btrfs-convert /