How to Add New Disks Using LVM to an Existing Centos 7

 LVM (Logical Volume Management) is a flexible and advanced option available to manage hard disks in most of the major Linux distributions. It is easy to manage the disks with LVM than the tradition tools like fdisk, parted or gparted.

Some of the terms which you need to understand while using LVM:

• Physical Volume (PV): Consists of Raw disks or RAID arrays or other storage devices.
• Volume Group (VG): Combines the physical volumes into storage groups.
• Logical Volume (LV): VG’s are divided into LV’s and are mounted as partitions.

In this article, we will take you through the steps to configure Disks using LVM in existing Linux machine by creating PV, VG’s and LV’s.

Note: If you don’t what to use LVM, you can add disk directly to an existing Linux system using these guides.

1. How to Add a New Disk to Linux System
2. How to Add a New Disk Larger Than 2TB to Linux System

Let’s consider a scenario where there are 2 HDD of 20GB and 10GB, but we need to add only 2 partitions one of 12GB and another 13GB. We can achieve this using LVM method only.

Once the disks has been added, you can list them using the following command.

# fdisk -l

Verify Hard Disks

1. Now partitions both the disks /dev/xvdc and /dev/xvdd using fdisk command as shown.

# fdisk /dev/xvdc
# fdisk /dev/xvdd

Use n to create the partition and save the changes with w command.

Partition Hark Disks

2. After partitioning, use the following command to verify the partitions.

# fdisk -l

Verify New Partitions

3. Create Physical Volume (PV).

# pvcreate /dev/xvdc1
# pvcreate /dev/xvdd1

Create Physical Volume

4. Create Volume Group (VG).

# vgcreate testvg /dev/xvdc1 /dev/xvdd1

Here, “testvg” is the VG name.

Create Volume Group

5. Now use “vgdisplay” to list all details about the VG’s in the system.

# vgdisplay
OR
# vgdisplay testvg

List Volume Group

6. Create Logical Volumes (LV).

# lvcreate -n lv_data1 --size 12G testvg
# lvcreate -n lv_data2 --size 14G testvg

Here, “lv_data1” and “lv_data2” are LV name.

Create Logical Volumes

7. Now use “lvdisplay” to list all details about the Logical volumes available in the system.

# lvdisplay
OR
# lvdisplay testvg

List Logical Volumes

8. Format the Logical Volums (LV’s) to ext4 format.

# mkfs.ext4 /dev/testvg/lv_data1
# mkfs.ext4/dev/testvg/lv_data2

Format LV to Ext4 Format

9. Finally, mount the file system.

# mount /dev/testvg/lv_data1 /data1
# mount /dev/testvg/lv_data2 /data2

Make sure to create data1 and data2 directories before mounting the filesystem.

Mount Filesystem

Source : https://www.tecmint.com/add-new-disks-using-lvm-to-linux/