How To Add a New Disk in CentOS 7

Learn how to add a new hard drive with commands to CentOS 7 in a simple way.

Before Connecting Hard Drive

First of all, we must know how is the structure of CentOS 7 before the installation of the new hardware, for this we must be as root users and execute the following command:

fdisk -l

Once the hard disk is connected, run the same command, fdisk -l. As we can see the new hard drive, 20 GB, is assigned to the path /dev/sdb.

This name will be assigned taking into account the type of disk; if we use a virtual hard drive, it will be /dev/xvdc.

Partition the New Hard Drive in Linux

Once the new hard disk has been identified, the next step will be to partition it, for this we will use the following syntax:

fdisk /dev/sdb

Common fdisk parameters are:

n: Create a new partition.

p: Print the partition table.

d: Remove a partition.

q: It leaves without saving the changes.

w: Save the changes and exit the command.

With this in mind we will perform the following process once the fdisk /dev/sdb command has been executed:

  • Enter the letter n to create the new partition.
  • Enter the letter p to define what is a primary partition.
  • Number 1 to establish a single partition of the new disk.
  • Establish the value of the first sector which is 2048 by default.
  • Establish the value of the last sector which is by default 41943039.
  • Save the changes using the letter w.

We can see that the process is executed correctly. If we rerun fdisk -l we can look at the changes in the new disk (/dev/sdb) :

Format the New Hard Drive

The next step is to format the new hard drive with the desired file system using the command

mkfs (make file system)

mkfs.ext4 /dev/sdb1

Finally, we mount the new disk in the desired location, in this tutorial we have created a new directory called /data :

mount /dev/sdb1 /data

If we want that partition to be mounted permanently, it will be necessary to edit the file /etc/fstab using the preferred editor and to enter the following line. We keep the changes.

/dev/sdb1 /data ext4 defaults 0 0

In this way, we have added the new hard drive in CentOS 7 and we are ready to take full advantage of it.

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  1. If I create a / home folder on the second drive, will it merge with the / home folder on the first drive? Can not be afraid of data loss of the first disk?

    1. No it will not. It is a separate file system.
      With the above example you would have to copy files from /data/home to /home.

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