Filesystems

This page serves to give some information on possible filesystems for Linux machines, in particular those that may be used for very large filesystems (many TB).

Ext3

• fairly old, but well established and well behaved
• does not support more than 16GB
• does not support transparent compression
• does not support checksumming (a data-integrity feature)

Ext4

• fairly new in Linux kernel (since 2.6.27 or so)
• becoming the default of new Linux distros
• no 16 GB limitation
• no compression and checksumming (data-integrity) features

XFS

• SGI's filesystem that was ported to Linux some years ago
• no 16 GB limitation
• no compression and checksumming (data-integrity) features

ZFS

• Sun's filesystem which is natively available on Solaris and OpenSolaris (both of which are freely available)
• there are ports of ZFS to FreeBSD and Mac OSX
• the source code license of ZFS is incompatible with the GPL of the Linux kernel; nevertheless Sun is considering a kernel port (see http://www.wizy.org/wiki/ZFS_on_FUSE)
• available as userland filesystem (ZFS-over-FUSE) on Linux; installable packages are available e.g. on latest Ubuntu und Fedora (see http://www.linux-magazine.com/w3/issue/103/ZFS.pdf)

btrfs

• latest addition to native Linux filesystems; stable version since 2.6.31 kernel (http://www.h-online.com/open/Kernel-Log-2-6-31-Tracking--/features/113671)
• a review of btrfs from an ex-ZFS engineer: http://lwn.net/Articles/342892/
• you can upgrade an existing linux file system to btrfs without destroying the existing fs or duplicating the data: http://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3
• http://www.h-online.com/open/The-Btrfs-file-system--/features/113738