Some points for later understanding and usage
Protective MBR is for backward comparability.
Primary GPT size = 512 * 34 = 17408 bytes or 17Kb
Secondary GPT size = 512 * 33 = 16896 bytes
We will create a 100Mb disk(my.img) with three partitions P1 -> 30MB P2-> 30Mb and P2->Rest
=============Script Start===============
#!/bin/bash
truncate -s 100MiB my.img
parted my.img mklabel gpt /*Create a GPT Table*/
parted my.img mkpart primary ext4 2MiB 30MiB /*create Partition P1*/
parted my.img mkpart primary ext4 30MiB 60MiB /*create Partition P2*/
parted my.img mkpart primary ext4 60MiB 99MiB /*create Partition P3*/
/*Find the free loop device*/
(base) vijay@INDD611T72:~$ sudo losetup -f
[sudo] password for vijay:
/dev/loop2
sudo losetup -P /devloop2p1 my.img
sudo mkfs.ext4 /dev/loop2p1
sudo mkdir -p /mnt/P1
sudo mkdir -p /mnt/P2
sudo mkdir -p /mnt/P3
sudo mount /dev/loop2p1 /mnt/P1
sudo mount /dev/loop2p2 /mnt/P2
sudo mount /dev/loop2p3 /mnt/P3
#Copy the required files to the respective partitions
sudo sync
sudo umount /mnt/P1
sudo umount /mnt/P2
sudo umount /mnt/P3
sudo rm -rf /mnt/P1
sudo rm -rf /mnt/P2
sudo rm -rf /mnt/P3
sudo losetup -d /dev/loop2
=============Script End===============
Extracting GPT table:
We can extract the GPT table out from the image using following dd commands.
dd if=./my.img of=./gpt-prim.bin skip=0 bs=512 count=34
/** primary (34 * 512) bytes**/
dd if=./my.img of=./gpt-bkup.bin skip=204767 bs=512 count=33
/** 100mb -(512*33) = (204767*512) **/
Steps done in PC for reference:
Copy the contents after mounting each partitions individually.
Ref: https://unix.stackexchange.com/questions/87183/how-to-create-a-formatted-partition-image-file-from-scratch
