btrfs
Btrfs Management
File System Management
| Command |
Description |
mkfs.btrfs /dev/sdX |
Create a new Btrfs filesystem |
mount /dev/sdX /mnt |
Mount Btrfs filesystem |
umount /mnt |
Unmount filesystem |
btrfs filesystem show |
Show Btrfs filesystems |
btrfs filesystem df /mnt |
Show space usage |
btrfs filesystem usage /mnt |
Detailed space usage |
RAID Management
| Command |
Description |
mkfs.btrfs -d raid1 -m raid1 /dev/sdb /dev/sdc |
Create RAID1 (mirror) |
mkfs.btrfs -d raid0 -m raid0 /dev/sdb /dev/sdc |
Create RAID0 (striping) |
mkfs.btrfs -d raid10 -m raid10 /dev/sdb /dev/sdc /dev/sdd /dev/sde |
Create RAID10 |
btrfs device add /dev/sdd /mnt |
Add device to filesystem |
btrfs device remove /dev/sdc /mnt |
Remove device from filesystem |
btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt |
Convert existing FS to RAID1 |
btrfs balance start /mnt |
Rebalance data across devices |
btrfs device stats /mnt |
Show device stats |
Subvolume Management
| Command |
Description |
btrfs subvolume create /mnt/data |
Create subvolume |
btrfs subvolume list /mnt |
List subvolumes |
btrfs subvolume delete /mnt/data |
Delete subvolume |
btrfs subvolume snapshot /mnt/data /mnt/data-snap |
Snapshot a subvolume |
btrfs subvolume snapshot -r /mnt/data /mnt/data-ro |
Create readonly snapshot |
Snapshots
| Command |
Description |
btrfs subvolume snapshot /mnt/data /mnt/data-snap |
Create snapshot |
btrfs subvolume delete /mnt/data-snap |
Delete snapshot |
btrfs send /mnt/data-snap (pipe) btrfs receive /mnt/backup |
Send snapshot to another FS |
Scrub & Check
| Command |
Description |
btrfs scrub start /mnt |
Start scrub on mounted FS |
btrfs scrub status /mnt |
Show scrub status |
btrfs scrub cancel /mnt |
Cancel scrub |
btrfs check /dev/sdX |
Check filesystem (offline) |
btrfs rescue super-recover /dev/sdX |
Try to recover superblock |
Resize
| Command |
Description |
btrfs filesystem resize +10G /mnt |
Grow FS by 10G |
btrfs filesystem resize -5G /mnt |
Shrink FS by 5G |
btrfs filesystem resize max /mnt |
Use full device size |
Example Workflows
Create RAID1 (mirror) with 2 disks:
mkfs.btrfs -d raid1 -m raid1 /dev/sdb /dev/sdc
mount /dev/sdb /mnt
Add new disk to pool and rebalance into RAID1:
btrfs device add /dev/sdd /mnt
btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt
Create snapshot and restore:
btrfs subvolume snapshot /mnt/data /mnt/data-snap
btrfs subvolume delete /mnt/data
btrfs subvolume snapshot /mnt/data-snap /mnt/data
| Option |
Description |
compress=zstd |
Zapne kompresi (doporučené: zstd) |
compress=lzo |
Komprese LZO (rychlá, méně efektivní) |
compress-force=zstd |
Vynutí kompresi všech dat |
autodefrag |
Automatická defragmentace při zápisu |
ssd |
Optimalizace pro SSD (obvykle se detekuje automaticky) |
ssd_spread |
Alternativní strategie zápisu na SSD |
space_cache=v2 |
Rychlejší mount díky cache alokací (novější verze) |
discard=async |
Asynchronní TRIM pro SSD |
noatime |
Nezapisuje access time (lepší výkon) |
nodatacow |
Vypne Copy-on-Write pro daný mount/subvolume |
subvol=<name> |
Mount konkrétního subvolume |
subvolid=<id> |
Mount podle ID subvolume |
/dev/sdb /mnt btrfs defaults,compress=zstd,autodefrag,ssd,discard=async 0 0
