[LINUX] Consolidate multiple disks into one using LVM

0. Overview

Recently, with the increasing functionality of media devices, the number of large-capacity items such as images and moving images is increasing. When data is stored on various HDDs, there is a problem that it becomes difficult to find which data is on which HDD. Therefore, I would like to bundle multiple HDDs and handle them as one large-capacity HDD. This time, I will explain how to bundle multiple HDDs using LVM.

1. Prerequisites

--A total of 5 HDDs

--Each HDD is 8TB

--Integrate capacity into two groups

2. Disk consolidation

2.1. Checking the disk

First, check the disk information from the following to confirm the name of the disk to be integrated.

$ sudo fdisk -l

# ------------------------------------------------------------------ #
Disk /dev/sdf: 7.3 TiB, 8001563222016 bytes, 15628053168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


Disk /dev/sdg: 7.3 TiB, 8001563222016 bytes, 15628053168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


Disk /dev/sdh: 7.3 TiB, 8001563222016 bytes, 15628053168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


Disk /dev/sdd: 7.3 TiB, 8001563222016 bytes, 15628053168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


Disk /dev/sde: 7.3 TiB, 8001563222016 bytes, 15628053168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
# ------------------------------------------------------------------ #

Also check the serial number to make sure it is not mistaken for another HDD.

$ sudo smartctl -a /dev/sde | grep Model

# ------------------------------------------------------------------ #
Device Model:     ST8000VN004-2M2101
# ------------------------------------------------------------------ #

Also check that it is not mounted.

$ df -h

If it is mounted, unlock it below

$ umount <YOUR MOUNT POINT>

2.2. Disk initialization

Initialize 5 disks

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

Do the same for sde, sdf, sdg, sdh.

2.3. Disk consolidation (grouping)

Next, integrate the initialized disks. This time, sdd, sde, sdf, sdg, sdh`` 8TB disks For 3 for 1 and 2 for 1, that is, 24TB and 16TB logical drives Integrate and build.

First, integrate from 24TB.

$ sudo vgcreate exthd1Group /dev/sdd /dev/sde /dev/sdf

# ------------------------------------------------------------------ #
Volume group "exthd1Group" successfully created
# ------------------------------------------------------------------ #

Similarly, do the 16TB one.

$ sudo vgcreate exthd2Group /dev/sdg /dev/sdh

2.4. Disk Consolidation (Create Volume)

Next, create a logical volume. Create a logical volume by specifying ʻexthd1Group` of the HDD group created above.

$ sudo lvcreate -l 100%FREE -n lv0 exthd1Group

# ------------------------------------------------------------------ #
  Logical volume "lv0" created.
# ------------------------------------------------------------------ #

Similarly, do for ʻexthd2Group`.

$ sudo lvcreate -l 100%FREE -n lv0 exthd2Group

If you do not want to use up all the capacity, you can change -l 100% FREE to -L 8T. lv0 refers to the name of the logical volume.

2.5. Disk consolidation (volume check)

Check the created volume.

$ sudo lvdisplay
# ------------------------------------------------------------------ #
  --- Logical volume ---
  LV Path                /dev/exthd2Group/lv0
  LV Name                lv0
  VG Name                exthd2Group
  LV UUID                
  LV Write Access        read/write
  LV Creation host, time N/A, 2020-02-10 14:09:41 +9999
  LV Status              available
  # open                 0
  LV Size                14.55 TiB
  Current LE             3815442
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:3

  --- Logical volume ---
  LV Path                /dev/exthd1Group/lv0
  LV Name                lv0
  VG Name                exthd1Group
  LV UUID                
  LV Write Access        read/write
  LV Creation host, time N/A, 2020-02-10 14:09:35 +9999
  LV Status              available
  # open                 0
  LV Size                21.83 TiB
  Current LE             5723163
  Segments               3
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2
# ------------------------------------------------------------------ #

All you have to do is format and use it.

2.6. Disk consolidation (volume initialization)

Format the volume of each HDD group with ʻext4. First, for the volume of ʻexthd1Group.

$ sudo mkfs -t ext4 /dev/exthd1Group/lv0

Similarly, for volumes of ʻexthd2Group`.

$ sudo mkfs -t ext4 /dev/exthd2Group/lv0

2.7. Disk integration (mounting)

First, check the created and initialized volume.

$ sudo fdisk -l

# ------------------------------------------------------------------ #
Disk /dev/mapper/exthd1Group-lv0: 21.9 TiB, 24004685463552 bytes, 46884151296 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes


Disk /dev/mapper/exthd2Group-lv0: 14.6 TiB, 16003123642368 bytes, 31256100864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
# ------------------------------------------------------------------ #

It's well done. Now, mount these.

$ sudo mount   /dev/exthd1Group/lv0 ./hdd1
$ sudo mount   /dev/exthd2Group/lv0 ./hdd2

If you want to mount automatically at startup, check the volume ʻUUID of each integrated HDD group and describe it in fstab. First, check ʻUUID.

$ sudo blkid /dev/exthd1Group/lv0

# ------------------------------------------------------------------ #
/dev/exthd1Group/lv0: UUID="7ii63fbf-deed-4ff1-b4af-8156f" TYPE="ext4"
# ------------------------------------------------------------------ #

Similarly, check ʻexthd2Group`.

$ sudo blkid /dev/exthd2Group/lv0

# ------------------------------------------------------------------ #
/dev/exthd2Group/lv0: UUID="8ii63fbf-deed-4ff1-b4af-8156f" TYPE="ext4"
# ------------------------------------------------------------------ #

Finally, write in fstab.

$ sudo vim /etc/fstab

# ------------------------------------------------------------------ #
Postscript
UUID=7ii63fbf-deed-4ff1-b4af-8156f     /hdd1    ext4   defaults        0 3
UUID=8ii63fbf-deed-4ff1-b4af-8156f     /hdd2    ext4   defaults        0 3
# ------------------------------------------------------------------ #

99. Delete groups and PV

If you already have evidence of using LVM when doing pvcreate,

$ sudo pvdisplay

Check the existing disk in to see the PV and which group the PV belongs to. If it is Unkown, it is likely that the physical device was pulled out after creating the group.

To be consistent, remove Unkown by doing the following:

$ sudo vgreduce --removemissing <YOUR_GROUP>

Then delete the group.

$ sudo vgremove <YOUR_GROUP>

Delete PV.

$ sudo pvremove <YOUR_PV>