How to Create and Convert Linux File Systems
Steps to Create and Convert Linux File Systems
The file system refers to a structure or a rule for operating systems to store the files in disk or partition. File systems has some types like extended file systems ext2, ext3 and ext4.
Second Extended File System - ext2
It is developed by Remy Card, which is introduced in 1993. In several Linux distro like RedHat and Debian, it was considered as the first default file system. It is used to overcome the legacy " ext" file system limitation with Flash based storage media like USB Flash drive, SD Card. 16GB &ndash 2TB is its maximum size but journaling feature is not available.
Third Extended File System - ext3
It was integrated in Kernel 2.4.15 with journaling feature, which was introduced in 2001. It provides facility to upgrade from ext2 to ext3 file systems without back up and to restore data. 16GB &ndash 2TB is its maximum size.
Fourth Extended File System - ext4
Here stable code were merged in the Kernel 2.6.28, which was introduced in 2008. It contains ext4 file system to Turn Off journaling feature. It has an additional features like Sub Directory Scalability, Multiblock Allocation, Delayed Allocation and Fast FSCK. Its maximum file size is 16GB to 16TB and as well as Backward compatibility.
To Determine the File System Type
Run the following command as a root user to determine the linux file system type on your machine.
[root@linuxhelp ~]# df -hT | awk ' {print $1,$2,$NF}' | grep " ^/dev"
/dev/sda3 xfs /
/dev/sda1 xfs /boot
/dev/sr0 iso9660 x86_64
To Create An Extended File Systems
Execute the mke2fs or mkfs commands after creating the file system using fdisk or parted command. Before this process ensure to replace the device path.
Before executing these commands, take backup of your important data to avoid data-loss.
Here are the partition’ s I have created in /dev/sdb hard drive as follows.
[root@linuxhelp ~]# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000b5211
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 5122047 2048000 82 Linux swap / Solaris
/dev/sda3 5122048 41943039 18410496 83 Linux
Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x59d5ea56
Device Boot Start End Blocks Id System
/dev/sdb1 2048 4196351 2097152 83 Linux
/dev/sdb2 4196352 8390655 2097152 83 Linux
/dev/sdb3 8390656 12584959 2097152 83 Linux
/dev/sdb4 12584960 20971519 4193280 5 Extended
/dev/sdb5 12587008 16781311 2097152 83 Linux
To Create ext2 File System for the partitions /dev/sdb1 and /dev/sdb2
[root@linuxhelp ~]# mkfs.ext2 /dev/sdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
[root@linuxhelp ~]# mkfs.ext2 /dev/sdb2
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
To Create ext3 File System for /dev/sdb3 partition
[root@linuxhelp ~]# mkfs.ext3 /dev/sdb3
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
To Create ext4 File System for /dev/sdb5 partition
[root@linuxhelp ~]# mkfs.ext4 /dev/sdb5
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
Create directories under /mnt for the mount point.
[root@linuxhelp ~]# mkdir /mnt/disk1
[root@linuxhelp ~]# mkdir /mnt/disk2
[root@linuxhelp ~]# mkdir /mnt/disk3
[root@linuxhelp ~]# mkdir /mnt/disk4
Now mount all partitions.
[root@linuxhelp ~]# mount /dev/sdb1 /mnt/disk1
[root@linuxhelp ~]# mount /dev/sdb2 /mnt/disk2
[root@linuxhelp ~]# mount /dev/sdb3 /mnt/disk3
[root@linuxhelp ~]# mount /dev/sdb5 /mnt/disk4
[root@linuxhelp ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 18G 4.0G 14G 23% /
devtmpfs 486M 0 486M 0% /dev
tmpfs 494M 140K 494M 1% /dev/shm
tmpfs 494M 7.1M 487M 2% /run
tmpfs 494M 0 494M 0% /sys/fs/cgroup
/dev/sda1 497M 116M 382M 24% /boot
/dev/sr0 3.9G 3.9G 0 100% /run/media/root/CentOS 7 x86_64
/dev/sdb1 2.0G 3.0M 1.9G 1% /mnt/disk1
/dev/sdb2 2.0G 3.0M 1.9G 1% /mnt/disk2
/dev/sdb3 2.0G 3.1M 1.8G 1% /mnt/disk3
/dev/sdb5 2.0G 6.0M 1.8G 1% /mnt/disk4
Run the below command to verify about file system in your machine.
[root@linuxhelp ~]# df -hT | awk ' {print $1,$2,$NF}' | grep " ^/dev"
/dev/sda3 xfs /
/dev/sda1 xfs /boot
/dev/sr0 iso9660 x86_64
/dev/sdb1 ext2 /mnt/disk1
/dev/sdb2 ext2 /mnt/disk2
/dev/sdb3 ext3 /mnt/disk3
/dev/sdb5 ext4 /mnt/disk4
Here you can see we have extended partitions ext2, ext3 and ext4.
To Convert An Extended File Systems
It is recommended to unmount all the partitions before converting.
[root@linuxhelp ~]# umount /mnt/disk1
[root@linuxhelp ~]# umount /mnt/disk2
[root@linuxhelp ~]# umount /mnt/disk3
[root@linuxhelp ~]# umount /mnt/disk4
To Convert ext2 to ext3
Use the following command to change an ext2 file system to ext3 with enabling the journal feature.
[root@linuxhelp ~]# tune2fs -j /dev/sdb1
tune2fs 1.42.9 (28-Dec-2013)
Creating journal inode: done
To Convert ext2 to ext4
Execute the below command to convert old ext2 to new ext4 file system with recent journaling feature.
[root@linuxhelp ~]# tune2fs -O dir_index,has_journal,uninit_bg /dev/sdb2
tune2fs 1.42.9 (28-Dec-2013)
Creating journal inode: done
To Convert ext3 to ext4
Use the below command to enable the ext4 features on an existing ext3 filesystem,
[root@linuxhelp ~]# tune2fs -O extents,uninit_bg,dir_index /dev/sdb3
tune2fs 1.42.9 (28-Dec-2013)
Run fsck to fix some on-disk structures, which modifies the tune2fs.
[root@linuxhelp ~]# e2fsck -f /dev/sdb1 e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/sdb1: 11/131072 files (0.0% non-contiguous), 25405/524288 blocks [root@linuxhelp ~]# e2fsck -f /dev/sdb2 e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/sdb2: 11/131072 files (0.0% non-contiguous), 25405/524288 blocks [root@linuxhelp ~]# e2fsck -f /dev/sdb3 e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/sdb3: 11/131072 files (0.0% non-contiguous), 25405/524288 blocks [root@linuxhelp ~]# e2fsck -f /dev/sdb5 e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/sdb5: 11/131072 files (0.0% non-contiguous), 26156/524288 blocks
mkdir /mnt/disk1
mkdir /mnt/disk2
mkdir /mnt/disk3
mkdir /mnt/disk4
Now mount all partitions.
mount /dev/sdb1 /mnt/disk
mount /dev/sdb2 /mnt/disk2
mount /dev/sdb3 /mnt/disk3
mkfs.ext2 /dev/sdb1
mkfs.ext2 /dev/sdb2
df -hT | awk ' {print $1,$2,$NF}' | grep " ^/dev"
tune2fs -j /dev/sdb1