The differences between Ext2 and Ext3 file systems are as follows.


Sl.No



EXT2




EXT3



Journaling




No journaling




Has journaling




Speed of file system(read-write)



Bit faster



Bit slower then ext2 file-system



Data corruption



File system may be corrupted due to unplanned reboots



Prevents file-system corruption 



Way to recover data



Require fsck to recover data after unplanned reboot



Does not require(automatic file recovery is done at booting time)



Online file system growth.



By default there is no Online file system growth.



Online file system growth



Commands to format



mkfs.ext2 or mke2fs



mkfs.ext3 or mke2fs -j



Max file size(if block size is 1kB)



2GB



16GB



De-fragmentation
Easy and done with e2defrag

There is no data security when doing de-fragmentation.



Data accommodation



More data can be accommodated in a give space



Less date is written when compare to ext2 in a give space due to journaling.


Some FAQ’s:

1. What is Journaling?
Ans : In general, Journaling file systems avoid file system corruption by maintaining a journal. The journal is a special file that logs the changes destined for the file system in a circular buffer. At periodic intervals, the journal is committed to the file system. If a crash occurs, the journal can be used as a checkpoint to recover unsaved information and avoid corrupting of file system meta-data.
2.How many file systems supported by linux? and what are they?
Ans : As of now(09-Nov-2009) Linux will supports : Btrfs, cifs, davfs, ext, ext2, ext3, ext4, exofs, hpfs, JFS minix, msdos, ncpfs, NiLFS(2), ntfs, nfs, proc, smbfs, iso9660, sysv, hpfs, affs, ufs, umsdos, vfat, xia, xfs, ZFS.
Note : Please add some more file systems which you people know in the comment section. So that i will update the post with new file systems.

3.What is the maximum size of a partition we can create using ext2 and ext3?
Ans : 4TB partition can be created in each ext2 and ext3 file system respectively.

4.What is the maximum size of a file we can create in ext2?
Ans : The maximum size what we can create is 2GB to 2TB. It depends on the block size we taken when we are formatting. If the block size is 1KB we can not create a file more than 2GB in ext2 file system.

5.What is “ext” in ext2 and ext3?
Ans : When linux first implemented the default file system is minixfs, in subsequent years it was replaced it’s successor file system called extended file-system. So the naming convention. So ext2 is second version of extended file system. Same explanation is given to ext3 and ext4.

6. Some points about ext4
a.It supports 64 bit storage limit’s, where as ext, ext2, ext3 are 32Bit storage limit’s and minix is 16Bit storage limit.
b.Have backward compatibility and performance is improved from lower version.
c.Extents are introduced (An extent is a range of contiguous physical blocks, improving large file performance and reducing fragmentation. A single extent in ext4 can map up to 128MB of contiguous space with a 4KB block size).

And there are many more advantages please see the below links for more info about all the file systems..
http://en.wikipedia.org/wiki/Ext4
http://en.wikipedia.org/wiki/Ext3
http://en.wikipedia.org/wiki/Ext2
http://en.wikipedia.org/wiki/Extended_file_system
http://www.ibm.com/developerworks/library/l-journaling-filesystems/index.html
http://www.oracle.com/technology/pub/articles/calish_filesys.html
http://www.cyberciti.biz/tips/understanding-unixlinux-file-system-part-i.html Please comment your thoughts regarding this post. To give feed back click here.

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Surendra Anne

Mr Surendra Anne is from Vijayawada, Andhra Pradesh, India. He is a Linux/Open source supporter who believes in Hard work, A down to earth person, Likes to share knowledge with others, Loves dogs, Likes photography. He works as Devops Engineer with Taggle systems, an IOT automatic water metering company, Sydney . You can contact him at surendra (@) linuxnix dot com.