Filesystem

File systems

• https://en.wikipedia.org/wiki/File_system#Disk_file_systems
• How to find out what filesystems Linux kernel supports
• Top 7 Best Linux File system: Ext4, BtrFS (high volume of data), JFS, ReiserFS, ZFS (dynamic disk striping and drive pooling), FAT32, exFAT.
• The 6 Best File Systems for Installing Linux. ext4, Btrfs, ZFS, Reiser4, XFS, JFS
• https://linuxjourney.com/. See 5 Free Online Games and Websites to Master Linux and the Command Line
• Filesystems on Linux: When Should You Not Use Ext4?
  • Btrfs supports snapshots and is self-repairing, while XFS excels with large file storage due to its parallel read and write operations.

squashfs

squashfs is a heavy-compression based read-only filesystem that is capable of compressing 2 to 3 GB of data onto a 700MB. Linux liveCD are built using squashfs. These CDs make use of a read-only compressed filesystem which keeps the root filesystem on a compressed file. It can be loopback mounted and loads a complete Linux env. Thus when some file are required by processes, they are decompressed and loaded onto the RAM and used.

• https://en.wikipedia.org/wiki/SquashFS
• http://squashfs.sourceforge.net/
• http://elinux.org/Squash_FS_Howto
• Ubuntu's snaps use the squashfs filesystem,
  • The snap file format is a single compressed SquashFS filesystem from Introduction to snapcraft.
  • A technical comparison between snaps and debs

# create a squashfs file
sudo mksquashfs /etc test.squashfs 

# mount the squashfs file 
mkdir /mnt/squash
mount -o loop compressedfs.squashfs /mnt/squash
# you can acess the contents at /mnt/squashfs

# exclude files 
sudo mksquashfs /etc test.squashfs -e /etc/passwd /etc/shadow
# or specify a list of exclude files given in a file
cat excludelist  # /etc/passwd
sudo mksquashfs /etc test.squashfs -ef excludelist

Btrfs

• https://en.wikipedia.org/wiki/Btrfs
• It's the default used by CauchyOS, Fedora, Garuda, and openSUSE.
• Fedora 33 launches with updated GNOME and BTRFS
• Install MX Linux with btrfs partitioning.
  • MX Linux 21: Dual-boot with Windows (& how to completely remove MX Linux and its bootloader) (video, Dec 2021) quite complete!
  • Although MX Linux does not use Btrfs as the default filesystem, users can install it if desired. Diving Into a Pool of Butter with MX-21 and Btrfs 2021

• (Very similar to above) Select EFI fat32 partition for ESP partition. EFI system partition/ESP from wikipedia.
• Garuda Linux uses the btrfs filesystem by default. See 6 Fun Linux Distros to Try if You're a Distro Hopper
• Modernize your Linux Storage with btrfs! (video)
• Used in Internal File Systems by Synology DiskStation DS223j
• Pros and Cons of Using Btrfs Filesystem in Linux

ZFS

• It's the default used by TrueNAS.
• Don't Use ZFS on Linux: Linus Torvalds
• Getting started with ZFS on Linux
• ZFS pool from Setting Up NAS Server On Proxmox. ZFS is different from other types of storage like Directory, LVM, etc.
  • It is easy to increase the volume. LXC -> Resources (VM does not have the "Resources" option) -> Root Disk -> Volume Action -> Resize (increase).

COW (copy on write) file system

The cow filesystem was found on xubuntu live CD. See http://en.wikipedia.org/wiki/Copy-on-write

How To Protect Your Server Against the Dirty COW Linux Vulnerability (10/21/2016)

Inode (index node)

• Everything You Ever Wanted to Know About inodes on Linux
• How do you see how many inodes are left on your system? df -i