In this article I am going to show you how to migrate your ext2 or ext3 partition to ext4. I will use a Ubuntu machine as an example. I want to warn you that you could lose data by doing this so, following good administrative practices, back up your data! Once you are certain you have that backup of your data, it’s time to begin.

Kernel pre-requisite

You must be certain you have a kernel that is at least 2.6.28-11-generic or higher. If not, do NOT continue on with this. To find out what kernel you are running issue the command uname -r. If your kernel is lower thatn 2.6.28-11 stop where you are and close your browser.

Step 1

The first step is to boot from a Ubuntu Live CD. You do this because you can’t convert a file system that has been mounted. If you are converting a second drive on your machine (one that doesn’t contain your OS or your ~/ (home) directory, you can always just unmount that drive and do this without booting the Live CD.

Step 2:

Now it’s time to convert. We’re going to use /dev/sda1 as an example for converting. You will want to know the exact name of the drive and/or partition you are wanting to covert. If you are converting from ext2 to ext4 issue the following commands:

sudo bash
tune2fs -O extents,uninit_bg,dir_index,has_journal /dev/sda1

If you are wanting to convert ext3 to ext4 issue the following commands:
sudo bash
tune2fs -O extents,uninit_bg,dir_index /dev/sda1

NOTE: After you enter either of the sudo bash commands you will have to enter your sudo password.

Step 3:

Regardless of which conversion you are doing you will want to check the drive (or partition) after the conversion and repair any issues. Do this with the command:

e2fsck -pf /dev/sda1

Step 4:

Now you need to make sure the partition will mount. Do this with the command:

sudo mount -t ext4 /dev/sda1 /mnt

Hopefully you won’t see any errors. You should now see the contents of that drive listed in the /mnt directory.

Step 5:

It’s time to edit your /etc/fstab file to reflect the change. Open this file up with your favorite text editor and look for the line that corresponds to the drive/partition you just changed. In that line you will reference to either ext2 or ext3. Change that reference to ext4. Save and close that file.

Step 6:

Now you need to refresh grub. Depending upon how your boot partition is will determine how you do this. If your boot partition is SEPARATE, do the following:

sudo bash
mkdir /mnt/boot
mount /dev/sda1 /mnt/boot
grub-install /dev/sda --root-directory=/mnt --recheck

If your boot partition is NOT separate, do the following:

sudo bash
mount /dev/sda1 /mnt
grub-install /dev/sda --root-directory=/mnt --recheck

Step 7:

Reboot. Once up and running you will now be using the ext4 file system!

Final thoughts

If you are leery of any of the above, don’t worry…you don’t HAVE to do this. Your system will run fine with ext2 or ex3. But if you love to get your hands dirty with your machines…then you will enjoy converting a working file system from one type to another. Just remember BACK UP YOUR DATA!

Users who want to create multiple partitions need a file called Hitachi Microdrive which contains the new driver that we are going to modify first and install afterwards. Unpack the package to a new directory on the hard drive. The first step is to find out the exact name of the USB stick that we want to use that way. The information can be found in the Windows Registry. Pressing [Windows R], typing [regedit] and hitting [Enter] will load the Registry editor.

The information are located in subkeys of the Registry key HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\USBSTOR. The name of the USB stick can be found by clicking on the [+] sign in front of the key. All USB devices should be listed there. The name of the USB stick can be copied by left-clicking the subkey, right-clicking afterwards and selecting Copy Key Name from the context menu.

The key needs to be modified because it contains the full path. The best way to do that is to paste the contents into a text editor and remove all chars before Disk&Ven.

Now that this is done we need to copy the part that is left into the Windows Clipboard again by selecting the text and pressing [CTRL C]

The driver information needs to be edited in the next step before the new drivers for the USB stick are installed. Load the file cfadisk.inf in an text editor and locate the [cfadisk_device] section.

Replace the chars IDE\DiskIBM-DSCM-11000__________________________SC2IC801 in the first line with the name of the USB stick that you are going to use. Remove every other line in the category so that only the line with our modified USB stick name is shown in there.

The driver is now prepared and can be installed for the USB stick. Open the Windows Control Panel, the System category and there the Hardware tab. A click on Device Manager will load the Windows Device Manager which lists the computer hardware. The USB stick should be located in the Disk Drives category. Right-click the USB stick and select Update Driver from the context menu.

The Hardware Update wizard should pop up. Select the option Install from a list or specific location in the window and click next.

Check the Don’t search. I will choose the driver to install option in the next window and click next again.

A click on Have Disk in the next window will open a file browser. Locate and pick the file cfadisk.inf that has been modified previously. Clicking on OK will check the driver and show a warning message that the driver is not digitally signed. Press next on that screen.

Ignore the warning message and continue by clicking Yes. Windows should now start the installation of the driver for the USB stick and display a message that it finished the installation.

Windows is now requesting a reboot of the system to load the updated drivers properly. The USB stick should now be recognized as a hard drive. This makes it possible to create multiple partitions on the USB stick with a software partition program.

Please note that only systems with the updated drivers will recognize the additional partitions. Connected the USB stick to a computer without the modified drivers will only show the first partition of the USB stick.