Storagenode: allow configuring database path independently (v1.4.2 and above only)

[Alexey]

The migration to LVM is possible in-place, if you have more free space than used.
Example with a virtual disk:

prepare a test lab disk and a random data

@Alexey

I would emulate this on loop devices

1. Create images for the disks

$ truncate -s 1G disk1.raw
$ truncate -s 3G disk3.raw

2. Create a loop device to emulate a disk

$ sudo losetup -f disk3.raw

3. find which one loop devices has been created

$ losetup | grep disk
/dev/loop2         0      0         0  0 /home/ubuntu/disk3.raw                  0

4. Create a GPT partition table:

$ sudo parted /dev/loop2 mklabel gpt
$ sudo partprobe /dev/loop2

5. Create a Primary partition

$ sudo parted /dev/loop2 mkpart primary ext4 1MiB 2.999GiB

6. Format it to ext4

$ sudo mkfs -t ext4 /dev/loop2p1

7. Create a mount folder

$ sudo mkdir /mnt/storj

8. Mount a disk

$ sudo mount /dev/loop2p1 /mnt/storj
$ sudo chown $(id -u) /mnt/storj

9. Copy the example file to that disk

$ cp disk1.raw /mnt/storj/

10. make an md5sum file to check that the file is not corrupted (this is not necessary, but allows to check that everything went well)

$ pushd /mnt/storj
/mnt/storj ~
$ md5sum disk1.raw > disk1.raw.md5

11. Checking:

$ md5sum -c disk1.raw.md5
disk1.raw: OK
$ popd
~

12. The current state is your initial state to emulate a storagenode, but with only one file disk1.raw 1GiB in size. Here you need to stop and remove the storagenode container, but not in this test lab

Convert the disk with GPT to LVM on the fly

1. unmount the disk, because ext4 doesn’t allow to shrink it online or you can resize your disk using GPart or KDE Partition Manager to free-up 1.1GiB of the disk space, then create a PV on it, and they will do this automatically, but we will continue in the CLI:

$ sudo umount /mnt/storj

2. check the filesystem

$ sudo e2fsck -f /dev/loop2p1
e2fsck 1.47.0 (5-Feb-2023)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/loop2p1: 13/196608 files (0.0% non-contiguous), 31037/785920 blocks

3. resize a filesystem

$ sudo resize2fs /dev/loop2p1 1900M
resize2fs 1.47.0 (5-Feb-2023)
Resizing the filesystem on /dev/loop2p1 to 486400 (4k) blocks.
The filesystem on /dev/loop2p1 is now 486400 (4k) blocks long.

4. shrink the partition (note - the size should be +1MiB)

$ sudo parted /dev/loop2 resizepart 1 1901MiB
Warning: Shrinking a partition can cause data loss, are you sure you want to continue?
Yes/No? y
Information: You may need to update /etc/fstab.

5. check fs:

$ sudo e2fsck -f /dev/loop2p1
e2fsck 1.47.0 (5-Feb-2023)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/loop2p1: 13/122880 files (0.0% non-contiguous), 26411/486400 blocks

6. mount it back (and here you can run your storagenode back)

$ sudo mount /dev/loop2p1 /mnt/storj

7. check that our data is ok

$ pushd /mnt/storj
/mnt/storj ~
$ md5sum -c disk1.raw.md5
disk1.raw: OK
$ popd
~

8. Create an LVM PV on the free space

$ sudo parted /dev/loop2 mkpart primary 1901MiB 100%
$ sudo parted /dev/loop2 set 2 lvm on
$ sudo partprobe /dev/loop2

9. create a new PV

$ sudo pvcreate /dev/loop2p2
  Physical volume "/dev/loop2p2" successfully created.

10. Create VG

$ sudo vgcreate vg0 /dev/loop2p2
  Volume group "vg0" successfully created

11. Create LV

$ sudo lvcreate -l 100%FREE vg0
  Logical volume "lvol0" created.

12. find our new lvm device

$ lsblk | grep lvm
  └─vg0-lvol0 254:0    0   1.1G  0 lvm

13. format our new LVM volume

$ sudo mkfs -t ext4 /dev/mapper/vg0-lvol0
mke2fs 1.47.0 (5-Feb-2023)
Discarding device blocks: done
Creating filesystem with 299008 4k blocks and 74880 inodes
Filesystem UUID: 13e90432-1592-4476-912e-c9ec7642bee0
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

14. Mount a new lvm volume

$ sudo mkdir /mnt/storj-new
$ sudo mount /dev/mapper/vg0-lvol0 /mnt/storj-new
$ sudo chown $(id -u) /mnt/storj-new

15. Migrate your data from /mnt/storj/ to /mnt/storj-new, but we will do only one sync for this test lab:

$ rsync -aP /mnt/storj/ /mnt/storj-new/
sending incremental file list
./
disk1.raw
  1,073,741,824 100%  104.56MB/s    0:00:09 (xfr#1, to-chk=2/4)
disk1.raw.md5
             44 100%    0.10kB/s    0:00:00 (xfr#2, to-chk=1/4)

16. (here we need to stop and remove the storagenode container and make a last rsync with a --delete option and run the container back with a new path /mnt/storj-new). The node is now running and online using the new storage location.
17. unmount the old location

$ sudo umount /mnt/storj

18. create a new PV

$ sudo pvcreate /dev/loop2p1
WARNING: ext4 signature detected on /dev/loop2p1 at offset 1080. Wipe it? [y/n]: y
  Wiping ext4 signature on /dev/loop2p1.
  Physical volume "/dev/loop2p1" successfully created.

19. extend vg0 with a new PV

$ sudo vgextend vg0 /dev/loop2p1
  Volume group "vg0" successfully extended

20. forbid coming a new data to the second PV, all new data will go to the first PV

$ sudo pvchange -xn /dev/loop2p2
  Physical volume "/dev/loop2p2" changed
  1 physical volume changed / 0 physical volumes not changed

21. move the data from the second PV to a first one on the fly (the storagenode will be online). This operation can be resumed, if there would be an interruption, it’s pretty safe.

$ sudo pvmove /dev/loop2p2
  /dev/loop2p2: Moved: 5.14%
  /dev/loop2p2: Moved: 100.00%

22. remove the second PV after all data has been moved to a first PV

$ sudo vgreduce vg0 /dev/loop2p2
  Removed "/dev/loop2p2" from volume group "vg0"
$ sudo pvremove /dev/loop2p2
  Labels on physical volume "/dev/loop2p2" successfully wiped.

23. remove the second partition and extend a first one

$ sudo parted /dev/loop2 rm 2
Information: You may need to update /etc/fstab.

$ sudo parted /dev/loop2 resizepart 1 100%
Information: You may need to update /etc/fstab.

$ sudo partprobe /dev/loop2

24. extend PV

$ sudo pvresize /dev/loop2p1
  Physical volume "/dev/loop2p1" changed
  1 physical volume(s) resized or updated / 0 physical volume(s) not resized

25. check names of our VG and LV

$ sudo lvs
  LV    VG  Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lvol0 vg0 -wi-ao---- 1.14g

26. extend LV

$ sudo lvextend -l +100%FREE -r vg0/lvol0
  Size of logical volume vg0/lvol0 changed from 1.14 GiB (292 extents) to <3.00 GiB (767 extents).
  Logical volume vg0/lvol0 successfully resized.
resize2fs 1.47.0 (5-Feb-2023)
Filesystem at /dev/mapper/vg0-lvol0 is mounted on /mnt/storj-new; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mapper/vg0-lvol0 is now 785408 (4k) blocks long.

27. check the data

$ pushd /mnt/storj-new
/mnt/storj-new ~
$ md5sum -c disk1.raw.md5
disk1.raw: OK
$ popd
$ df -h /dev/mapper/vg0-lvol0
Filesystem             Size  Used Avail Use% Mounted on
/dev/mapper/vg0-lvol0  3.0G  1.1G  1.8G  37% /mnt/storj-new