Linux file systems: ext4, Btrfs, XFS and ZFS

In short: A file system organises how data is stored on a drive. On Linux ext4 is the common default, Btrfs and ZFS offer snapshots and checksums, XFS is strong with large files.

In more detail: The choice affects safety, speed and functions such as undoing changes.

In detail

File system	Strength	Note
ext4	robust, fast, supported everywhere	default on Debian, Ubuntu
Btrfs	snapshots, compression, checksums, subvolumes	default on Fedora, openSUSE
XFS	very large files and servers	default on RHEL
ZFS	checksums, RAID, snapshots, replication	licence question, much RAM, servers/NAS
F2FS	for flash storage	phones, SD cards
exFAT, NTFS	exchange with Windows	NTFS via the ntfs3 driver

• Journaling: protects against broken structures at power loss.
• Copy-on-write: Btrfs/ZFS never write over old data, so snapshots are cheap.
• Checksums: detect silent data errors (“bit rot”).
• Commands: df -h (space), lsblk -f (file systems), mkfs.ext4 /dev/sdX1, fsck, mount.
• Mount configuration: /etc/fstab.
• Snapshots with Btrfs: btrfs subvolume snapshot / /snap/before-update. Tools: Snapper, Timeshift.
• RAID: does not replace a backup.

See also: Partitions, LVM and encryption (LUKS), Linux file system hierarchy (FHS)