IIRC once you mount an ext2/3 volume as ext4, you can't go back. ext4 has made a lot of improvements, but has also had a lot of corruption issues, even if corn

IIRC once you mount an ext2/3 volume as ext4, you can't go back. ext4 has made a lot of improvements, but has also had a lot of corruption issues, even if corner cases. If you don't need extremely large files or extremely cluttered directory structures, you don't _need_ ext4, though I haven't compared directly in a few years, and I suspect a lot of these stability issues have shaken out. The worst I experienced was kvm guests with ext4 filesystems stored in files on ext4 filesystems causing the not only the guest, but often the _host_ filesystem to go corrupt. Obviously, using LVM volumes or basically anything but filesystem images for production VMs would have avoided this, but the infrastructure I supported at the time already had a lot of this in place and too many other problems to solve to focus on it.