Btrfs filesystem

vergelijkbaar met unix zfs
- a ‘NAS’ type of filesystem
- ingebakken software raid
- self-healing fs (zfs : automically , btrfs : on command)
- options such as quota , compression etc

docu

https://btrfs.wiki.kernel.org/index.php/Main_Page
https://wiki.archlinux.org/title/Btrfs

diff zfs & btrfs
btrfs is native linux , zfs for linux is a port to linux
zie : https://www.salvagedata.com/btrfs-zfs-xfs-ext4-how-are-they-different/
https://www.reddit.com/r/btrfs/comments/vf2u17/btrfs_vs_zfs/
https://www.wundertech.net/btrfs-vs-zfs-comparison/

used/free space

General linux userspace tools such as df(1) will inaccurately report free space on a Btrfs partition.
It is recommended to use :

btrfs filesystem usage /media/ward/UD-9TB/

install

btrfs is directly supported by the linux kernel.
it is alreay installed in LXM
You can install it for your root partition way easier, and it’s more flexible.
E.g. you can easily change your layout by rebalancing blocks. e.g. migrate from JBOD to RAID1 to RAID10 to RAID5/6, without having to reformat.

mount

specif options for btrfs : https://btrfs.readthedocs.io/en/latest/ch-mount-options.html

raid

RAID works in btrfs, but RAID 5/6 are experimental and there is a slim chance of botching a filesystem.
Other raid modes have the upside of being more flexible, as you can mix and match different sized drives and easily rebalance.
ZFS has a solid RAID5/6 mode and the community is larger as it is older.

compression

BTRFS supports automatic compression
(great on single thread , much io , but perfomance hit with multi thread )

maintenance

to manually defragment :

btrfs filesystem defragment -r /media/ward/UD-9TB/

Btrfs scrub is an online file system checking tool.
It reads all the data and metadata on the file system and uses checksums and the duplicate copies from RAID storage to identify and repair any corrupt data.

A running scrub process will prevent the system from suspending, see this thread for details.
Start manually

# To start a (background) scrub on the file system which contains `/`:
btrfs scrub start /media/ward/UD-9TB/

# To check the status of a running scrub:
btrfs scrub status /media/ward/UD-9TB/