The ext3 file system is an enhanced VERSION of the ext2 file system. The most important difference between the Ext2 and Ext3 is that Ext3 supports journaling.

Ext2 is a LEGACY file system has LOYS SHORTCOMINGS. In case of a system crash or unexpected power failure or unclean reboot of the system, the system administrator needs to check all ext2 mounted drives for consistency. This needs to be performed an e2fsck program. This is a time-consuming process and during this time, any data on volumes is unreachable.

Ext3 is a newer filesystem with supports journaling.  Journaling feature in ext3 file systems eliminates the requirement of consistency check of the file system in case of a system crash or unclean reboot. The only possible situation of consistency check requirement in ext3 is with hardware failures. In such a case, recovery time depends on hardware speed, storage performance, and system RESOURCES. File size and a number of files do not create any impact, normally journaling complete consistency check in a few seconds.