Ext4 – Fourth Extended File System
- Ext4, the high-anticipated Ext3 successor.
- On October 2008, Ext4 as stable code were merged in the Kernel 2.6.28 which contains Ext4 file system.
- Backward compatibility.
- Max file size 16GB to 16TB.
- Ext4 file system have option to Turn Off journaling feature.
- Other features like Sub Directory Scalability, Multiblock Allocation, Delayed Allocation, Fast FSCK etc.
Ext3 – Third Extended File System
- Ext3 file system was introduced in 2001 and same was integrated in Kernel 2.4.15 with journaling feature, which is to improve reliability and eliminates need to check file system after unclean shutdown.
- Max file size 16GB – 2TB.
- Provide facility to upgrade from Ext2 to Ext3 file systems without having to back up and restore data.
As you know , The Extended File System is Ext3 on pcDuino 3.
Ext4 is better than Ext3. So
We want to upgrade upgrade from Ext3 To Ext4 without formatting Nand (Hard disk).
Here is a simple steps on the pcDuino Forum : http://pcduino.com/forum/index.php?topic=4475.msg7006#msg7006
Upgrade From Ext3 To Ext4 in detail :
Step 1: Display File System Ext3
Type “df -T ” to display file system with print type.
You’ll see currentaly file system type is ext3 on the first line of Type.
ubuntu@ubuntu:~$ df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/nandd ext3 3749816 1360444 2202212 39% / none devtmpfs 447644 4 447640 1% /dev none tmpfs 448464 4 448460 1% /tmp none tmpfs 89696 252 89444 1% /run none tmpfs 5120 0 5120 0% /run/lock none tmpfs 448464 132 448332 1% /run/shm none tmpfs 448464 92 448372 1% /var/tmp none tmpfs 448464 624 447840 1% /var/log
Step 2: root user
OK. Let us change to root user.
ubuntu@ubuntu:~$ sudo passwd Enter new UNIX password: (-type passwd,such as pcDuino ) Retype new UNIX password:(-type passwd again ,such as pcDuino ) passwd: password updated successfully ubuntu@ubuntu:~$ su - Password: (-type passwd again, such as pcDuino) root@ubuntu:~#
Step 3:Converting Ext3 to Ext4
To enable the ext4 features on an existing ext3 filesystem, use the command.
root@ubuntu:~# tune2fs -O extents,uninit_bg,dir_index /dev/nandd tune2fs 1.42 (29-Nov-2011)
WARNING: You cannot revert or mount back to ext3 filesystem once you run above command.
After running this command we MUST run fsck to fix up some on-disk structures that tune2fs has modified.
Step 4: e2fsck nand
root@ubuntu:~# e2fsck -pf /dev/nandd /dev/nandd is mounted. WARNING!!! The filesystem is mounted. If you continue you ***WILL*** cause ***SEVERE*** filesystem damage. Do you really want to continue<n>? (type "y", hit [Enter] keyboard) Do you really want to continue<n>? yes /dev/nandd: recovering journal (Wait a minute) /dev/nandd: recovering journal /dev/nandd: One or more block group descriptor checksums are invalid. FIXED. /dev/nandd: Group descriptor 10 checksum is invalid. /dev/nandd: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY. (i.e., without -a or -p options) root@ubuntu:~#
Step 4: fsck nand
root@ubuntu:~# fsck -pf /dev/nandd -y fsck from util-linux 2.20.1 e2fsck: Only one of the options -p/-a, -n or -y may be specified. root@ubuntu:~#
Step 5: reboot
Step 6: Be patient for waiting fsck inode
fscking on nand is slow, just be patient..
After reboot, you’ll see like this . It means fscking Indoe : )
Until finish about 5 minutes 🙂
/dev/nandd: ***** FILE SYSTEM WAS MODIFIED*****
then upgrade successfully.
and then it goes to desktop
Step 7: Upgrade to Ext 4
Type ” df -T” agian on Terminal:
ubuntu@ubuntu:~$ df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/nandd ext4 3749816 1358304 2204352 39% / none devtmpfs 447644 4 447640 1% /dev none tmpfs 448464 4 448460 1% /tmp none tmpfs 89696 260 89436 1% /run none tmpfs 5120 0 5120 0% /run/lock none tmpfs 448464 132 448332 1% /run/shm none tmpfs 448464 72 448392 1% /var/tmp none tmpfs 448464 628 447836 1% /var/log