"If you’re a Linux user, you’ve likely been asked at
some point if you want Ext3, Ext4, XFS, ReiserFS, Btrfs, or one of
many other filesystem acronyms. This choice confuses new and old
users alike, and like all software, the options change as
technology improves. Many people probably don’t care what
filesystem they use as long as it’s stable and reasonably
fast, but how do you know which one that is? This guide will
attempt to cover the basic differences between the most common
options, and provide the pros and cons of each choice.
"Ext2 is Linux’s “old standby” filesystem. It
was the default for most of the major early Linux distributions.
While it has been mostly supplanted by versions 3 and 4, ext2 is
still popular on USB and other solid-state devices. This is because
it does not have a journaling function, so it generally makes fewer
reads and writes to the drive, effectively extending the life of
the device. Recommended Use: USB/Solid State Drives, or any cause
where you need high stability with minimal reads/writes."