We can create a loop device in Linux which we can use as a virtual device for experiment. Following steps will show how to create loop device and use it for creation of file system.
- Add new device
# losetup -f
/dev/loop0
- Create a file which will serve as virtual device.
# dd if=/dev/urandom of=/bhushan bs=1M count=128
128+0 records in128+0 records out
134217728 bytes (134 MB, 128 MiB) copied, 12.9207 s, 10.4 MB/s
- Setup up the mapping between loop device and new file
# losetup /dev/loop0 /bhushan
- Use new virtual device for file system creation
# mkfs -t ext4 /dev/loop0
mke2fs 1.43.3 (04-Sep-2016)
Discarding device blocks: done
Creating filesystem with 131072 1k blocks and 32768 inodes
Filesystem UUID: 7be2cbaf-a2a5-4319-a7e9-51b749c69184
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
# mount -t ext4 /dev/loop0 /mnt
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/loop0 120M 1.6M 110M 2% /mnt1
# umount /mnt1
- Detach a file from loop device
# losetup -d /dev/loop0
