Using loopback files

Loopback filesystems are very interesting components of Linux-like systems. We usually create filesystems on devices (for example, disk drive partitions). These storage devices are available as device files such as /dev/device_name. In order to use the storage device filesystem, we mount it at a directory called a mount point . On the other hand, loopback filesystems are those that we create in files rather than a physical device. We can then mount those files as filesystems at a mount point. This essentially lets you create logical "disks" inside a file on your physical disk!

How to do it...

Let us see how to create an ext4 filesystem on a file of size 1 GB:

1. The following command will create a file that is 1 GB in size:

   $ dd if=/dev/zero of=loobackfile.img bs=1G count=1
   1024+0 records in
   1024+0 records out
   1073741824 bytes (1.1 GB) copied, 37.3155 s, 28.8 MB/s
   

   You can see that the size of the created file exceeds 1 GB. This is because the hard disk is a block device and...