Setting Up and Mounting a External Disk in RHEL: Step-by-Step Guide

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This guide explains how to verify, partition, format, and mount a new disk (/dev/sda) on Red Hat Enterprise Linux (RHEL). Each step includes commands and detailed explanations to simplify the process.

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Prerequisites

Before we start, ensure you have:

• Administrative access to the RHEL system

• A new disk attached to your system

• Basic knowledge of Linux command-line operations

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Step-by-Step Guide

Step 1: Verify the Disk

Why: Ensure the disk (/dev/sda) is available, unpartitioned, and ready for use.

Commands:

df -hT
lsblk
sudo fdisk -l /dev/sda

Explanation:

• lsblk: Lists block devices, showing names, sizes, and mount points. Check if sda is listed as unmounted.

• sudo fdisk -l /dev/sda: Displays detailed disk information, including partition status and usage.

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Step 2: Partition the Disk

Why: Partitioning prepares the disk for formatting and data storage.

Command:

sudo fdisk /dev/sda

Steps:

1. Press n to create a new partition.

2. Once inside fdisk:

   • Press n to create a new partition.

   • Select p for a primary partition.

   • Accept the default partition number (e.g., 1) and press Enter.

   • Accept the default first and last sector to use the entire disk.

   • Press w to write changes and exit.

3. Press w to save changes and exit.

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Step 3: Format the Partition

Why: Apply a filesystem for data storage.

sudo mkfs.xfs /dev/sda1

• Explanation: Formats the partition /dev/sda1 with the XFS filesystem.

• Replace xfs with another filesystem (e.g., ext4) if desired.

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Step 4: Create a Mount Point

Why: A mount point is a directory where the disk will be accessible. We’re creating /app as our mount point.

Command:

sudo mkdir -p /app

• Explanation

  • mkdir creates a directory named /app if it doesn’t already exist.

  • This directory will serve as the interface for the mounted disk.

Step 5: Mount the Partition

Why: Before making the mount permanent, test if the partition can be mounted successfully.

Command:

sudo mount /dev/sda1 /app

Explanation

• Mounts /dev/sda1 (the newly formatted partition) at /app.

• Any files written to /app will now reside on the mounted disk

Step 6: Make the Mount Permanent

Why?

The mount will disappear after a reboot unless made permanent by adding it to /etc/fstab.

Commands

1. Get the UUID:

    sudo blkid /dev/sda1
   

   

   1. Copy the above mentioned UUID and edit fstab

2. Edit /etc/fstab:

    sudo nano /etc/fstab
   

Explanation

• blkid shows the UUID of /dev/sda1.

• Add the following line to /etc/fstab to persist the mount:

    UUID=<your-uuid> /app xfs defaults 0 0
  

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Step 7: Verify the Mount

Why?

Ensure the disk is mounted correctly and persists after reboots.

Command

sudo mount -a
df -hT

Explanation

• mount -a applies all /etc/fstab entries.

• df -hT confirms the mount status and filesystem type.

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Conclusion

You’ve successfully set up, formatted, mounted, and configured a persistent disk in RHEL. The disk is now ready for use and will remain accessible after reboots. Regular backups and monitoring are recommended to maintain data integrity and system reliability.

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FAQ

Q1: What are the benefits of using mkfs.ext4?

• Ans: mkfs.ext4 is a widely used command for formatting partitions with the ext4 filesystem, known for its performance and reliability.

Q2: How often should I perform a disk check?

• Ans:- It's advisable to perform a disk check monthly or as part of your regular maintenance schedule.

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