107 lines
3.5 KiB
Markdown
107 lines
3.5 KiB
Markdown
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---
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title: "Linux: How to create LVM logical volume"
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date: "2022-05-15"
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---
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### First step: creating a physical volume
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After you have attached the disk to a physical server or virtual machine, you need to type
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this command:
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```bash
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sudo fdisk -l
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```
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<!--more-->
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to make sure the drive is recognized by the operating system, and to identify the drive name. Output
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of command will be something like this:
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```plaintext
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Disk /dev/vdb: 10 GiB, 10737418240 bytes, 20971520 sectors
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Units: sectors of 1 * 512 = 512 bytes
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Sector size (logical/physical): 512 bytes/512 bytes
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I/O size (minimum/optimal): 512 bytes/512 bytes
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```
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Once you have identified the drive name (in our case it is `/dev/vdb`), you can create
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physical volume using the command:
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```bash
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sudo pvcreate /dev/vdb
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```
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You will see output like this:
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```plaintext
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kostya@ubuntu-21-04:~$ sudo pvcreate /dev/vdb
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Physical volume "/dev/vdb" successfully created.
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kostya@ubuntu-21-04:~$
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```
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### Step two: create the volume group
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Now we need to create a volume group. This is done by the following command:
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```bash
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sudo vgcreate {vgname} {pvname}
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```
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In our case, the command will look like this:
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```bash
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sudo vgcreate vg-example /dev/vdb
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```
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The command output will look like this:
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```plaintext
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kostya@ubuntu-21-04:~$ sudo vgcreate vg-example/dev/vdb
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Volume group "vg-example" successfully created
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kostya@ubuntu-21-04:~$
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```
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### Step three: creating the logical volume
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Creating a logical volume can be done with the following command:
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```bash
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sudo lvcreate --size {size} --name {lv-name} {vg-name}
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```
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In our case, it will be:
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```bash
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sudo lvcreate --size 5G --name lv-example vg-example
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```
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You will see output like this:
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```plaintext
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kostya@ubuntu-21-04:~$ sudo lvcreate --size 5G --name lv-example vg-example
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Logical volume "lv-example" created.
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kostya@ubuntu-21-04:~$
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```
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If you want the logical volume to use all the free space in the volume group, then run the command:
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```bash
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sudo lvcreate --extents 100%FREE --name lv-example vg-example
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```
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### Fourth step: creating the filesystem
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To create an xfs filesystem, type the command:
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```bash
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sudo mkfs.xfs /dev/vg-example/lv-example
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```
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The command output will look like this:
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```plaintext
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kostya@ubuntu-21-04:~$ sudo mkfs.xfs/dev/vg-example/lv-example
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meta-data =/dev/vg-example/lv-example isize = 512 agcount = 4, agsize = 327680 blks
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= sectsz = 512 attr = 2, projid32bit = 1
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= crc = 1 finobt = 1, sparse = 1, rmapbt = 0
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= reflink = 1 bigtime = 0
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data = bsize = 4096 blocks = 1310720, imaxpct = 25
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= sunit = 0 swidth = 0 blks
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naming = version 2 bsize = 4096 ascii-ci = 0, ftype = 1
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log = internal log bsize = 4096 blocks = 2560, version = 2
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= sectsz = 512 sunit = 0 blks, lazy-count = 1
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realtime = none extsz = 4096 blocks = 0, rtextents = 0
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Discarding blocks ... Done.
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kostya@ubuntu-21-04:~$
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```
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To create an ext4 filesystem, replace the `mkfs.xfs` command with `mkfs.ext4`
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### Step Five: Mount the Logical Volume
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For example, suppose you want to mount the newly created logical volume to the `/opt` folder. In this
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case, add this line to file `/etc/fstab`:
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```bash
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/dev/vg-example/lv-example /opt xfs defaults 0 1
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```
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After that, type the command:
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```bash
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sudo mount -a
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```
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You can verify that the logical volume has been mounted successfully using the command:
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```bash
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df -h /opt
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```
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The output should be like this:
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```plaintext
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kostya@ubuntu-21-04:~$ df -h /opt/
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Filesystem Size Used Avail Use% Mounted on
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/dev/mapper/vg--random-lv--random 5.0G 68M 5.0G 2% /opt
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kostya@ubuntu-21-04:~$
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```
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