Originaly stolen from Linuxgeek.net
Ext2fs'
maximum size is 8GB, and can have maxinum filesize of Xgb. Ext2fs is still under development (it doesn't mean that it is unstable but means that there are things that can be improved or implemented), and it's planned to include easy restoration of deleted file, Access Control List (for security), and automatic file compression. Some beta-quality variants of Ext2fs include Encrypted Ext2fs and journaling Ext2fs.
Ext3
The ext3 filesystem is a journaling extension to the standard ext2 filesystem on Linux. Journaling results in massively reduced time spent recovering a filesystem after a crash, and is therefore in high demand in environments where high availability is important, not only to improve recovery times on single machines but also to allow a crashed machine's filesystem to be recovered on another machine when we have a cluster of nodes with a shared disk. Maximum file system size 4 Terabytes, Maximum file size 2 Gigabytes.
Reiserfs
is a filesystem using a plug-in based object oriented variant on classical balanced tree algorithms. ReiserFS has fast journaling, which means that you don't spend your life waiting for fsck. ReiserFS does meta-data journaling, enabling fast crash recovery without the expense of full data journaling. maximum file system size 16 Terabytes. Maximum files size 210 petabytes.
