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< User:Chrismurphy

Revision as of 16:29, 12 August 2020 by Kparal (talk | contribs) (improve formatting)


LVM commands Btrfs commands Note
pvs,pvdisplay btrfs filesystem show shows all btrfs, mounted or not
vgs,vgdisplay btrfs device usage /mnt device allocation info
btrfs filesystem usage /mnt most complete command
lvs btrfs subvolume list not exact analogs
lvdisplay btrfs subvolume show not exact analogs
pvcreate+vgextend+lvresize+resize2fs/xfs_growfs+(fsadm resize) btrfs device add /dev/ /mnt mkfs and resize are implied
(fsadm resize)+resize2fs/xfs_growfs+lvresize+vgreduce+pvcreate btrfs device remove /dev/ /mnt data migration, resize, magic wipe are implied
resize2fs/xfs_growfs btrfs filesystem resize
pvmove btrfs replace; or preferred; new drive must be equal to or larger than old
btrfs device add; then
btrfs device remove
mkfs and resize are implied
data migration, resize, magic wipe are implied
lvcreate btrfs snapshot create
lvcreate --snapshot btrfs subvolume snapshot -r lvm snapshots are initially ro, btrfs snapshots are rw unless -r is used
lvremove btrfs subvolume delete
? btrfs filesystem du btrfs specific du, shows total, shared, and exclusive usage for a subvolume or directory; only comes into play with snapshotting and reflinks, otherwise it'll match regular du
? btrfs scrub start/status/cancel/resume online metadata/data integrity check, only csum verification, is not an fsck


Why do 'du' and 'btrfs filesystem du' totals differ? 
Most likely due to inline extents. du will compute small files with a minimum 4KiB, the data block size. But the actual storage consumption of small files when inline (saved with the inode metadata in a leaf, hence inline) is quite a bit less.