Filesystems: Difference between revisions

630 bytes added ,  24 September 2009
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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).
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). The list is sorted by age!


== Ext3 ==
== Ext3 ==
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* does not support transparent compression  
* does not support transparent compression  
* does not support checksumming (a data-integrity feature)
* 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 ==
== XFS ==
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== ZFS ==
== ZFS ==
* Sun's filesystem which is natively available on Solaris and OpenSolaris (both of which are freely available)
* Sun's filesystem which is natively available on Solaris and OpenSolaris (both of which are freely available)
* (optional) transparent (gzip) compression (LZO compression available as patch)
* atomic updates - means that the on-disk state is consistent at all times, there's no need to perform a lengthy filesystem check after forced reboots/power failures
* background checksumming and self-healing for data integrity
* Built-in stripes (RAID-0), mirrors (RAID-1) and RAID-Z (it's like software RAID-5, but more efficient due to ZFS's copy-on-write transactional model)
* there are ports of ZFS to FreeBSD and Mac OSX
* 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)
* the source code license of ZFS is incompatible with the GPL of the Linux kernel, therefore only available as userland filesystem (ZFS-over-FUSE; see see http://www.wizy.org/wiki/ZFS_on_FUSE) on Linux
* 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)
* installable ZFS/FUSE packages are available e.g. on latest Ubuntu und Fedora (see http://www.linux-magazine.com/w3/issue/103/ZFS.pdf)
 
== Ext4 ==
* fairly new in Linux kernel (since 2.6.27 or so); ext4 is based on ext3 (same developers)
* becoming the default of new versions of Linux distros (Fedora, Ubuntu, ...)
* no 16 GB limitation
* no compression and checksumming (data-integrity) features


== btrfs ==
== 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)
* latest addition to native Linux filesystems; considered stable since 2.6.31 kernel (http://www.h-online.com/open/Kernel-Log-2-6-31-Tracking--/features/113671)
* (optional) transparent compression
* checksumming for data integrity is implemented
* a review of btrfs from an ex-ZFS engineer: http://lwn.net/Articles/342892/
* 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  
* 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
* http://www.h-online.com/open/The-Btrfs-file-system--/features/113738
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