Upgrading from ext3 to ext4 in Ubuntu

If you have installed Ubuntu recently you will find that ext4 is the standard format used for creating filesystems. However, if you upgraded from an older version of Ubuntu you may be still using ext3.

The following instructions show how to upgrade the filesystem format with the data still in place. I am presuming you have a backup of your data in case this goes completely pear-shaped.

First confirm that you are using ext3 by typing the following command in a terminal window (Go to Applications menu, Accessories, Terminal)

sudo df -Th

One of the lines that showed up for me was

/dev/sdb1     ext3   241263968  93827044 137632456  41% /media/mirror

Now download, create and boot from a Ubuntu live CD so that none of your hard drives are in use.  Choose the 32-bit option of the latest version (ver 10.10 at time of writing) of Ubuntu.

Then restart the machine with this newly created CD and again confirm the name of the device you want to upgrade from ext3 to ext4.

sudo df -Th

Before making the change in format, let’s check the disk for any errors

sudo e2fsck -fDC0 /dev/sdb1

When that completed, we make the change from ext3 to ext4 with

sudo tune2fs -O extents,uninit_bg,dir_index /dev/sdb1

The only thing left to do is to edit the fstab file so that the filesystem loads with ext4

The fstab file will be on the drive that you use to boot the PC in the /etc directory.  Although not in my example here, this may be the drive you just modified.

We need to mount the drive that is used for booting (I assume it is sda1 here)

sudo mkdir /mnt/sda1
sudo mount -t ext4 /dev/sda1 /mnt/sda1

Now edit the fstab file

sudo nano /mnt/sda1/etc/fstab

Look for the line which contains your recently changed drive (sdb1 for me) and alter the format from ext3 to ext4 and hit control-x to exit.  Then hit the Y key to accept the changes and hit enter to replace the old fstab file.

Now it’s just a matter of restarting for the drive to be reloaded with ext4.