Moving CentOS 7 to LVM on Raspberry Pi 3 / ARMv7L

I will formalize this later when I can

  1. This is purely assuming you’re using CentOS 7 on RPI3 and have DD’ed the image per their installation instructions. This assumption will lead the below
  2. Confirm your version has support via CONFIG_BLK_DEV_INITRD kernel compile option. You can check /proc/config.gz for this..if you dont have it then modprobe configs
  3. Generate an initrd – dracut -f -v /boot/initrd $(uname -r)
  4. Append ‘initramfs initrd 0x01f00000’ to /boot/config.txt
  5. Modify /boot/cmdline.txt to read initrd=0x01f00000 after root=/dev/…. and before rootfstype=ext4
  6. Reboot as a test. Note that your boot time will go from about 5-10 seconds to upwards of a minute or so. You will see the Raspberry Pi splash screen for about 5 seconds as opposed to .5 or 1 second before. This is because the Pi now needs to load the 26MB initrd in to memory before continuing
  7. If it comes back up then you can move the file system now
  8. Edit /etc/fstab and change noatime for / to be ro,noatime
  9. Reboot
  10. yum install -y lvm2
  11. fdisk /dev/mmcblk0
  12. Create a new partition and exit
  13. Reboot
  14. pvcreate /dev/mmcblk0p4
  15. vgcreate root /dev/mmcblk0p4
  16. lvcreate –name=”lv_root” -l 45%FREE root <—- more on this later
  17. mkdir /mnt/new
  18. mount /dev/mapper/root/lv_root /mnt/new
  19. Copy the file system: tar -cvpf – –one-file-system –acls –xattrs –selinux / | tar xpf – -C /mnt/new/
  20. Edit /boot/cmdline.txt root= to be root=/dev/mapper/root-lv_root
  21. Reboot


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