Filesystems: Difference between revisions

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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). The list is sorted by age!
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 ==
* 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)


== XFS ==
== XFS ==
* SGI's filesystem that was ported to Linux some years ago
* SGI's filesystem (1994) that was ported to Linux around 2001
* no 16 GB limitation
* no 16 TB limitation; max size is 8 Eib (1 exbibyte = 2^60 bytes)
* no compression and checksumming (data-integrity) features
* no data compression and checksumming (data-integrity) features. It does have metadata checksums.
* the default for RHEL starting at version 7


== 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 (since 2005)) and OpenSolaris (both of which are freely available)
* no 16 TB limitation; max size is 2^128 bytes
* (optional) transparent (gzip) compression (LZO compression available as patch)
* (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
* 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  
* 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)
* 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
* triple parity raid (raidz3) has been added to ZFS [http://blogs.sun.com/ahl/entry/triple_parity_raid_z]
* 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
* there is a port of ZFS to FreeBSD
* installable ZFS/FUSE packages are available e.g. on latest Ubuntu und Fedora (see http://www.linux-magazine.com/w3/issue/103/ZFS.pdf)
* the source code license of ZFS is incompatible with the GPL of the Linux kernel, therefore not in the latter
* install from http://zfsonlinux.org/


== Ext4 ==
== Ext4 ==
* fairly new in Linux kernel (since 2.6.27 or so); ext4 is based on ext3 (same developers)
* ext4 is based on ext3 (same developers)
* becoming the default of new versions of Linux distros (Fedora, Ubuntu, ...)
* default of some Linux distros
* no 16 GB limitation
* no 16 TB limitation; max size is 1 EiB (1 exbibyte = 2^60 bytes)
* no compression and checksumming (data-integrity) features
* no compression and checksumming (data-integrity) features


== btrfs ==
== btrfs ==
* 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)
* latest addition to native Linux filesystems; considered stable since 2.6.31 kernel (2009; see http://www.h-online.com/open/Kernel-Log-2-6-31-Tracking--/features/113671)
* no 16 TB limitation; max size is 16 Eib (1 exbibyte = 2^60 bytes)
* (optional) transparent (zlib) compression
* (optional) transparent (zlib) compression
* checksumming for data integrity is implemented
* checksumming for data integrity is implemented

Latest revision as of 21:23, 28 November 2016

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!

XFS[edit | edit source]

  • SGI's filesystem (1994) that was ported to Linux around 2001
  • no 16 TB limitation; max size is 8 Eib (1 exbibyte = 2^60 bytes)
  • no data compression and checksumming (data-integrity) features. It does have metadata checksums.
  • the default for RHEL starting at version 7

ZFS[edit | edit source]

  • Sun's filesystem which is natively available on Solaris (since 2005)) and OpenSolaris (both of which are freely available)
  • no 16 TB limitation; max size is 2^128 bytes
  • (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)
  • triple parity raid (raidz3) has been added to ZFS [1]
  • there is a port of ZFS to FreeBSD
  • the source code license of ZFS is incompatible with the GPL of the Linux kernel, therefore not in the latter
  • install from http://zfsonlinux.org/

Ext4[edit | edit source]

  • ext4 is based on ext3 (same developers)
  • default of some Linux distros
  • no 16 TB limitation; max size is 1 EiB (1 exbibyte = 2^60 bytes)
  • no compression and checksumming (data-integrity) features

btrfs[edit | edit source]