Скачать или смотреть Managing RHEL 8 Loopback Devices, Partitions and Logical Volumes with Systemd

You may want to practice your Linux storage skills for exams or just to get better at your job. May be, you only have a single drive in your laptop or Raspberry Pi. Don't worry you can still create more partitions and logical volumes you just need to create a loopback device. You will find that you need to run partprobe to detect any partitions that you create, but it all works. The same goes with LVMs. They will all work but after a reboot we need to scan and load the metadata from the loopback device. To ensure all of this happens we can create a systemd service unit to carry out all the tasks for us on boot. Although we use Red Hat Enterprise Linux 8, this will run on any systemd based Linux distribution. Good luck!

[Unit]
Description=Activate loop device
DefaultDependencies=no
After=systemd-udev-settle.service
Before=lvm2-activation-early.service
Wants=systemd-udev-settle.service

[Service]
ExecStart=/sbin/losetup /dev/loop0 /volume.img
ExecStart=/sbin/partprobe /dev/loop0
ExecStart=/sbin/pvscan --cache:
Type=oneshot

[Install]
WantedBy=local-fs.target

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