How to create a file based filesystem using dd command on Linux

The following article will describe a procedure on how to create a file based filesystems using dd command on Linux.

First, create a zero filled file with a specific size using dd command. Below are few examples on how to create a such file of specific size:

$ dd if=/dev/zero of=file.fs bs=1024 count=1024000
$ dd if=/dev/zero of=file.fs bs=1024 count=102400
$ dd if=/dev/zero of=file.fs bs=1024 count=10240
$ dd if=/dev/zero of=file.fs bs=1024 count=1024

After execution of any of the above command you will now have file.fs file available in your current working directory. For example to create 10MB file execute:

$ dd if=/dev/zero of=file.fs bs=1024 count=10240
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0338773 s, 310 MB/s
$ ls

Next, create a filesystem of your choice using mkfs command:

  • mkfs.bfs
  • mkfs.cramfs
  • mkfs.ext2
  • mkfs.ext3
  • mkfs.ext4
  • mkfs.ext4dev
  • mkfs.fat
  • mkfs.minix
  • mkfs.msdos
  • mkfs.ntfs
  • mkfs.vfat

The below command will create vfat filesystem:

# mkfs.fat file.fs 
mkfs.fat 3.0.27 (2014-11-12)

Depending on what you need, now we are ready to create a mount point eg./mnt/tmp and mount our new filesystem:

# mkdir /mnt/tmp
# mount file.fs /mnt/tmp/

Confirm that the file system is mounted:

# mount | grep file.fs
/home/lubos/filefs/file.fs on /mnt/tmp type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=utf8,shortname=mixed,errors=remount-ro)
# cd /mnt/tmp/
# df -h .
Filesystem      Size  Used Avail Use% Mounted on
/dev/loop0       10M     0   10M   0% /mnt/tmp

Comments and Discussions
Linux Forum