Migrating a live system from ext3 to ext4 filesystem
This article is meant to serve as a guide for migrating a live system from ext3 to an ext4 filesystem, including migration of files to use extents, a major feature in ext4. It describes the entire migration procedure, including common pitfalls involving a migration of a live system, as opposed to doing a fresh install.
Reasons for conversion
The explanation of advantages and disadvantages of ext4 is beyond the scope of this article. If you are not affected by the limitations of ext3, and not willing to take risks, it may not be worth it. On the other hand, on successful completion of the migration procedure your system may perform faster, experience shortened file system checks, and have increased reliability with no ill effects.
Migrating to ext4
Word of warning
Do a backup before attempting this procedure. It may render your system unbootable, and may destroy your data.