Linux File System EXT3, EXT4, and XFS | Mounting partitions Temporarily and Permanently
This video explains the Linux file system and mount options.
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Description
Linux file system
EXT was the first Linux file system. It was used in early versions of Linux.
EXT2 was the second generation of the EXT file system. It provides very basic features. It was developed in 1980. It was the default file system before RHEL5.
EXT3 was the third generation of the EXT file system. It was the default file system in RHEL5. It was the first file system in the EXT series that supports the journaling mechanism. It supports a file up to 2 TB in size.
EXT4 is the fourth generation of the EXT file system. This was the default file system in RHEL6. It uses a series of contiguous physical blocks on the hard disk known as extents. The extents are used to improve the performance of very large files.
XFS was mainly developed for UNIX by Silicon Graphics. Later it was adopted by most Linux distributions including RHEL. It was the default file system in RHEL7. This file system is based on 64-bit extent. It uses journaling for metadata operations. It supports file systems and files of sizes up to 8 exabytes. The only drawback of this system is that it does not support the shrink feature like EXT3 and EXT4.
The mkfs command
We use the mkfs command with the t option to create a file system on a partition. This command needs two arguments: the file system's name and the partition's path. It creates the specified file system on the specified partition.
The mount command
We use the mount command to mount a partition temporarily. We can use it to mount any newly created partition or external file system to the Linux file system. It needs two arguments: the absolute path of the partition we want to mount and a mount point. A mount point is an access point of the partition. We can use any directory as a mount point. The mount command mounts the specified partition to the specified directory.
The /etc/fstab file
The /etc/fstab file stores mount points' information. The kernel reads this file at the boot time to mount partitions to the Linux file system. If we want to mount a partition permanently, we must create an entry for that partition in this file.
A fstab file entry has six fields. The following table explains their meanings.
Field Description
First It describes the device or partition's name we want to mount.
Second It describes the mount point's name.
Third It describes the file system of the partition.
Fourth It describes the mount options.
Fifth The dump command uses it to determine whether it should dump the mounted partition at the boot time.
Sixth The fsck command uses it to determine whether it should check and repair the mounted partition at the boot time.