[kwlug-disc] ext4

Chris Irwin chris at chrisirwin.ca
Fri May 7 15:54:19 EDT 2010

On Fri, May 7, 2010 at 11:48, William Park <opengeometry at yahoo.ca> wrote:
> On Wed, May 05, 2010 at 10:40:35AM -0400, Oksana Goertzen wrote:
>> Hello Everyone,
>> What are the advantages of going to ext4?  Is this something I can do "in
>> place"?  I was reading
>> http://ext4.wiki.kernel.org/index.php/Ext4_Howto#Converting_an_ext3_filesystem_to_ext4
> You can't upgrade in-place, and there is no real need to upgrade from
> ext3.  But, all my partitions are ext4.

Yes you can. You can either mount an ext3 filesystem as ext4. You will
have the benefit of the new run-time features such as delayed
allocation, but using the existing (and backwards-compatible) on-disk
features and format available in ext3.

You can also use tune2fs to enable ext4 features on-disk (such as
extents), but at this point your filesystem is no-longer backwards
compatible with ext3. Only new files will benefit from extents, as
existing data is left as-is.


>> I believe I'd have to modify /etc/fstab plus it says something about
>> modifying grub.  Would I need to do that on an Ubuntu system running
>> 10.04 (was upgraded)?  Anything else I'm missing?
> What does /etc/fstab have to do with GRUB/LILO?

You would have to rebuild your initrd, but you shouldn't need to
modify grub due to an fstab change. But you do need to run a version
of grub with ext4 support, which may require upgrading grub if you
don't have that now.

Chris Irwin
<chris at chrisirwin.ca>

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