LS201 Lab 17.3. - Exercise question: Using losetup and parted
while trying out the lab exercise 17.3 I came up with a couple questions that I dont seem to quite understand.
Q1) In the steps 3 and for of the exercise, we are asked to make three partitions (using pared). check partitioned file and then checking the loop devices for that partition with the following commands:
$ sudo parted -s /dev/loop1 unit MB mkpart primary ext4 0 256
$ fdisk -l /dev/loop1
$ ls -l /dev/loop1*
This works wonders when I use the parted command. However, if I partition the imagefile with the fdisk command instead, then the /dev/loop1px files are not created, so I cannot mount these partitions. If then I add a fourth partition but using the 'parted' command then all of the loop devices (loop1p1, loop1p2, loop1p3, loop1p4) are created in the dev directory. I am wondering why does this happen or if there is a way to make it create the loop device after using fdisk.
Q2) Same exercise I also noticed that I can partition either the imagefile directly or the loop device /dev/loopx. Do these two become the same after the losetup -f imagefile?
Q3) I tried to take the exercise a bit further and have the partitioned imagefile not only available at the moment but also after boot time. So I tried to edit the /etc/fstab file with:
/home/myuser/imagefile /home/myuser/mountdir ext4 loop,offset=501760 0 0
This of course, having my second partition start at 256 and having it with the file system ext4 like can be seen below:
$ sudo fdisk -l imagefile
Disk imagefile: 550 MiB, 576716800 bytes, 1126400 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
Disklabel type: dos
Disk identifier: 0xe79cfb62
Device Boot Start End Sectors Size Id Type
imagefile1 1 500000 500000 244.1M 83 Linux
imagefile2 501760 706559 204800 100M 83 Linux
imagefile3 706560 1126399 419840 205M 83 Linux
Obviously that did not work for me so I am trying to see how to make a loop device partition available after boot time.