GENERAL

create filesystem

mkfs.btrfs -f -L $LABEL $DEVICE1 $DEVICE2 ...

# mount subvolume with ssd options & lzo compression
UUID=$UUID $PATHTMP btrfs defaults,noatime,ssd,discard,autodefrag,compress=lzo,space_cache,inode_cache,subvol=save 0 2

# mount device with noauto mounting
UUID=$UUID $PATHTMP btrfs defaults,noauto,noatime0 2

BTRFS

btrfs filesystem

command group othat primarily does work on the whole filesystems

btrfs filesystem <subcommand> <args>
  show # show global configuration
  show $vol # show information
  usage $vol # show detailed information
  df $vol # list occupied spaces
  defragment $vol # defragment
  label $vol $label # get or set label to filesystem

btrfs subvolume

manage btrfs subvolumes

btrfs subvolume <subcommand> [<args>]
  create $path # create subvolume
  delete $path # delete subvolume
  list $path # list major properties of subvolume
  set-default $ID $path # set a subvolume a default of device

mount a subvolume

mount [-o ...] subvol=$path <device> <path-system>

btrfs property

get/set/list properties for given filesystem object

btrfs property <subcommand> <args>
  list $PATH # list properties of $PATH
  -ts list $PATH # list only rw properties of $PATH
  get $PATH # return rw property of $PATH
  set -ts $PATH ro false # set property of $PATH to RWrite
  set -ts $PATH ro true # set property of $PATH to ROnly

UUID

btrfstune -u /dev/sdaX # get UUID of device
btrfstune -U $UUID /dev/sdaX # set the UUID for device

INTEGRITY

btrfs device

manage devices of btrfs filesystems

btrfs device <subcommand> <args>
  stats $path-device # show history stats
  ready <device> # Wait until all devices of a multiple-device filesystem are scanned and registered within the kernel module
  scan <device> # Scan devices for a btrfs filesystem and register them with the kernel module

btrfs scrub

scrub btrfs filesystem, verify block checksums

btrfs scrub <subcommand> <args>
  start $path-device # start a scrub
  status $path-device  # return stats on scrub launched

btrfs check

check or repair an unmounted btrfs filesystem

btrfs check [options] <device>
btrfs check $vol # check an unmounted btrfs filesystem
  -b|--backup # use the first valid set of backup roots stored in the superblock
  --check-data-csum # verify checksums of data blocks
  --chunk-root <bytenr> # use the given offset bytenr for the chunk tree root
  -E|--subvol-extents <subvolid> # show extent state for the given subvolume
  -p|--progress # indicate progress at various checking phases

  --repair # enable the repair mode and attempt to fix problems where possible

SNAPSHOT

btrfs subvolume

manage btrfs subvolumes

btrfs subvolume <subcommand> [<args>]
  snapshot $vol $snap # create a RWrite snapshot
  snapshot -r $vol $snap # create a ROnly snapshot
  delete $vol/$snap # delete snapshot

  create [-i <qgroupid>] [<dest>/]<name> # Create a subvolume <name> in <dest>
     -i <qgroupid>Add the newly created subvolume to a qgroup
  delete [options] <subvolume> [<subvolume>...] # Delete the subvolume(s) from the filesystem
    -c|--commit-after # wait for transaction commit at the end of the operation
    -C|--commit-each # wait for transaction commit after deleting each subvolume
  find-new <subvolume> <last_gen> # List the recently modified files in a subvolume, after <last_gen> ID
  get-default <path> # Get the default subvolume of the filesystem <path>
  list [options] [-G [+|-]<value>] [-C [+|-]<value>] [--sort=rootid,gen,ogen,path] <path> # List the subvolumes present in the filesystem <path>
    -p # print parent ID
    -a # print all the subvolumes in the filesystem and distinguish between absolute and relative path with respect to the given <path>
    -c # print the ogeneration of the subvolume, aliases: ogen or origin generation
    -g # print the generation of the subvolume
    -o # print only subvolumes below specified <path>
    -u # print the UUID of the subvolume
    -q # print the parent uuid of subvolumes (and snapshots)
    -R # print the UUID of the sent subvolume, where the subvolume is the result of a receive operation
    -t # print the result as a table
    -s # only snapshot subvolumes in the filesystem will be listed
    -r # only readonly subvolumes in the filesystem will be listed
    -G [+|-]<value> # list subvolumes in the filesystem that its generation is >= ⟨+), <= (-)
    --sort=rootid,gen,ogen,path # list subvolumes in order by specified items

QGROUP

https://linuxfr.org/users/ar7/journaux/btrfs-et-opensuse-episode-5-les-quotas

BACKUP/RESTORE

https://ramsdenj.com/2016/04/05/using-btrfs-for-easy-backup-and-rollback.html
https://wiki.evolix.org/HowtoBTRFS
https://github.com/digint/btrbk

basic backup

    btrfs subvolume snapshot -r $vol $snap # create a ro snapshot
    btrfs send <snapshot> | gzip -c > $path # backup to compressed file
    gzip -dc $path | btrfs receive <pathto/> # restore from compressed file
    btrfs property set -ts  <pathto> ro false # to mount volume

credential backup

    btrfs subvolume snapshot -r / /my/snapshot-date && sync
    btrfs send /my/snapshot-YYYY-MM-DD | ssh user@host btrfs receive /my/backups
    btrfs subvolume snapshot -r / /my/incremental-snapshot-YYYY-MM-DD && sync
    btrfs send -p /my/snapshot-YYYY-MM-DD /my/incremental-snapshot-YYYY-MM-DD | ssh user@host btrfs receive /backup/home

save the streams

    btrfs subvolume snapshot -r / /my/snapshot-YYYY-MM-DD && sync
    btrfs send /my/snapshot-YYYY-MM-DD | ssh user@host 'cat >/backup/home/snapshot-YYYY-MM-DD.btrfs'
    btrfs subvolume snapshot -r / /my/incremental-snapshot-YYYY-MM-DD && sync
    btrfs send -p /my/snapshot-YYYY-MM-DD /my/incremental-snapshot-YYYY-MM-DD | ssh user@host 'cat >/backup/home/incremental-snapshot-YYYY-MM-DD.btrfs'

PARTCLONE

# clone, backup & restore partition
https://manpages.ubuntu.com/manpages/disco/man8/partclone.btrfs.8.html

# clone /dev/hda1 to hda1.img and display debug information.
partclone.ext3 -c -d -s /dev/hda1 -o hda1.img

# restore /dev/hda1 from hda1.img and display debug information.
partclone.extfs -r -d -s hda1.img -o /dev/hda1

# restore image from clonezilla(split, gzip,) with stdin source
cat sda1.ext3-ptcl-img.gz.a* | gunzip -c | partclone.ext3 -d -r -s - -o /dev/sda1

recover/rescue

https://ownyourbits.com/2019/03/03/how-to-recover-a-btrfs-partition/