Best Practice for Transferring Data To New Drive

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It’s not difficult, but requires to read a documentation.
I would emulate this on loop devices

  1. Create images for the disks
$ truncate -s 1G disk1.raw
$ truncate -s 1G disk2.raw
  1. Create loop devices to emulate disks
$ sudo losetup -f disk1.raw
$ sudo losetup -f disk2.raw
  1. find which one loop devices has been created
$ losetup | grep disk
/dev/loop6         0      0         0  0 /home/ubuntu/disk1.raw                  0     512
/dev/loop7         0      0         0  0 /home/ubuntu/disk2.raw                  0     512
  1. enter to an lvm shell
$ sudo lvm
  1. Add a new disk
lvm> pvcreate /dev/loop6
  Physical volume "/dev/loop6" successfully created.
  1. Create VG
lvm> vgcreate vg0 /dev/loop6
  Volume group "vg0" successfully created
  1. Create LV
lvm> lvcreate -l 100%FREE vg0
  Logical volume "lvol0" created.
  1. exit the lvm shell
lvm> exit
  1. find our new lvm device
$ lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
fd0           2:0    1    4K  0 disk
loop0         7:0    0 63.9M  1 loop /snap/core20/2105
loop1         7:1    0 63.9M  1 loop /snap/core20/2182
loop2         7:2    0 67.8M  1 loop /snap/lxd/22753
loop4         7:4    0 40.4M  1 loop /snap/snapd/20671
loop5         7:5    0 91.9M  1 loop /snap/lxd/24061
loop6         7:6    0    1G  0 loop
└─vg0-lvol0 253:0    0 1020M  0 lvm
loop7         7:7    0    1G  0 loop
loop8         7:8    0 38.8M  1 loop /snap/snapd/21465
sda           8:0    0   20G  0 disk
├─sda1        8:1    0 19.9G  0 part /
├─sda14       8:14   0    4M  0 part
└─sda15       8:15   0  106M  0 part /boot/efi
sr0          11:0    1   52K  0 rom
sr1          11:1    1 1024M  0 rom
  1. Format our new LVM volume
$ sudo mkfs -t ext4 /dev/mapper/vg0-lvol0
mke2fs 1.45.5 (07-Jan-2020)
Discarding device blocks: done
Creating filesystem with 261120 4k blocks and 65280 inodes
Filesystem UUID: f13cb690-c69c-43ae-90bc-36886da4b0b5
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376

Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
  1. Mount a new lvm volume
$ sudo mkdir /mnt/storj
$ sudo mount /dev/mapper/vg0-lvol0 /mnt/storj
$ sudo chown $(id -u) /mnt/storj/
  1. copy some file to there (to emulate data)
$ cp disk2.raw /mnt/storj/
  1. make an md5sum file to check that file is not corrupted (this is not necessary, but allows to check that everything went well)
$ md5sum /mnt/storj/disk2.raw > /mnt/storj/disk2.raw.md5
  1. checking:
$ md5sum -c /mnt/storj/disk2.raw.md5
/mnt/storj/disk2.raw: OK
  1. Now we are going to add a new disk to move data.
$ sudo pvcreate /dev/loop7
  Physical volume "/dev/loop7" successfully created.
  1. add it to vg0
$ sudo vgextend vg0 /dev/loop7
  Volume group "vg0" successfully extended
  1. Mark the first disk to be not used anymore (any new data will go to the second disk)
$ sudo pvchange -xn /dev/loop6
  Physical volume "/dev/loop6" changed
  1 physical volume changed / 0 physical volumes not changed
  1. now order to move data from the original disk to a new one
$ sudo pvmove /dev/loop6
  /dev/loop6: Moved: 32.55%
  1. wait until it finish (if something happen on this stage, except disk damaging, it is safe, you always can resume the move even after reboot)
  /dev/loop6: Moved: 100.00%
  1. remove the first disk from vg0
$ sudo vgreduce vg0 /dev/loop6
  Removed "/dev/loop6" from volume group "vg0"
  1. remove pv for the first disk
$ sudo pvremove /dev/loop6
  Labels on physical volume "/dev/loop6" successfully wiped.
  1. now check, that data didn’t damage
$ md5sum -c /mnt/storj/disk2.raw.md5
/mnt/storj/disk2.raw: OK
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