The Ext2 file system is the predecessor to Ext3. Ext2 is not journaled. As one of the earliest file systems on Linux, Ext2 has been heavily tested and improved over the years. This might be the reason why people often refer to it as rock-solid
.
Ext2 uses the POSIX access control model.
After a system outage when the file system cannot be cleanly unmounted, e2fsck starts to analyze the file system data. Metadata is brought into a consistent state and pending files or data blocks are written to a designated directory (called lost+found). In contrast to journaling file systems, e2fsck analyzes the entire file system and not just the recently modified bits of metadata. This takes significantly longer than checking the log data of a journaling file system. Depending on file system size, this procedure can take half an hour or more. Therefore, it is not desirable to choose Ext2 for any server that needs high availability.
Ext2 does not scale well to large volumes or to a great number of files.
Because Ext2 does not maintain a journal and uses significantly less memory, it is sometimes faster than other file systems.
Because Ext3 is based on the Ext2 code and shares its on-disk format as well as its metadata format, upgrades from Ext2 to Ext3 are very easy.