Editing Ext3 (section)

===Defragmentation===

{{Update section|date=January 2020}}

There is no online ext3 [[defragmentation]] tool that works on the filesystem level. There is an offline ext2 defragmenter, <code>e2defrag</code>. However, <code>e2defrag</code> may destroy data, depending on the feature bits turned on in the filesystem; it does not know how to handle many of the newer ext3 features.<ref>{{cite web|url=http://marc.info/?l=ext3-users&m=116231468911590&w=2|title=Post to the ext3-users mailing list|author=Andreas Dilger|work=ext3-users mailing list post}}</ref>

There are userspace defragmentation tools, like Shake<ref>[http://vleu.net/shake/ Shake]. Vleu.net. Retrieved on 2013-06-22.</ref> and defrag.<ref>[http://ck.kolivas.org/apps/defrag/ Defrag written in shell]. Ck.kolivas.org (2012-08-19). Retrieved on 2013-06-22.</ref><ref>[http://bazaar.launchpad.net/~jdong/pyfragtools/trunk/files Defrag written in Python]. Bazaar.launchpad.net. Retrieved on 2013-06-22.</ref> Shake works by allocating space for the whole file as one operation, which will generally cause the allocator to find contiguous disk space. If there are files which are used at the same time, Shake will try to write them next to one another. Defrag works by copying each file over itself. However, this strategy works only if the file system has enough free space. A true defragmentation tool does not exist for ext3.<ref>[http://www.redhat.com/archives/ext3-users/2005-March/msg00013.html RE: searching for ext3 defrag/file move program]. Redhat.com (2005-03-04). Retrieved on 2013-06-22.</ref>

However, as the Linux System Administrator Guide states, "Modern Linux filesystem(s) keep fragmentation at a minimum by keeping all blocks in a file close together, even if they can't be stored in consecutive sectors. Some filesystems, like ext3, effectively allocate the free block that is nearest to other blocks in a file. Therefore it is not necessary to worry about fragmentation in a Linux system."<ref>[http://www.tldp.org/LDP/sag/html/filesystems.html 5.10. Filesystems]. Tldp.org (2002-11-09). Retrieved on 2013-06-22.</ref>

While ext3 is resistant to file fragmentation, ext3 can get fragmented over time or for specific usage patterns, like slowly writing large files.<ref>{{cite web|url=http://trac.transmissionbt.com/ticket/849 |quote=The default Ubuntu filesystem ("ext3") will fragment large (>1GB), slowly growing files (<1&nbsp;MB/s)| title=#849 closed Enhancement (fixed) - preallocation to prevent fragmentation |work=trac.transmissionbt.com}}</ref><ref>{{cite web|quote=We found heavily fragmented free areas on an intensively used IMAP server which stores all its emails in individual files – although more than 900&nbsp;GB of the total disk space of 1.4&nbsp;TB were still available|url= http://www.heise-online.co.uk/open/Tuning-the-Linux-file-system-Ext3--/features/110398/3|date=27 October 2008|author=Oliver Diedrich|title=Tuning the Linux file system Ext3}}</ref> Consequently, ext4 (the successor to ext3) has an online filesystem defragmentation utility e4defrag<ref>[http://kernelnewbies.org/Ext4#head-38e6ac2b5f58f10989d72386e6f9cc2ef7217fb0 Ext4 – Linux Kernel Newbies]. Kernelnewbies.org (2011-05-19). Retrieved on 2013-06-22.</ref> and currently supports [[extent (file systems)|extents]] (contiguous file regions).