003 Configure Local Storage

Tech Tutorial: Configuring Local Storage on Red Hat Enterprise Linux #

Introduction #

In this tutorial, we are focusing on one of the critical objectives for the Red Hat Certified System Administrator (RHCSA) exam: configuring local storage. The ability to manage storage devices effectively is a fundamental skill for system administrators. We will cover how to list, create, and delete partitions on both MBR and GPT disks, create and manage logical volumes, and configure systems to mount file systems at or during boot.

Step-by-Step Guide #

Prerequisites #

  • A running Red Hat Enterprise Linux 8 system.
  • Sufficient permissions (typically root) to perform system configurations.
  • A spare storage device or virtual disk to practice on.

1. List Existing Storage Devices #

Before making any changes, it’s essential to understand the current storage setup. The lsblk command lists all block devices in a tree-like format.

lsblk

2. Partitioning Disks #

MBR vs. GPT Disks #

  • MBR (Master Boot Record): Supports up to 2TB disks and up to four primary partitions.
  • GPT (GUID Partition Table): Supports larger disks and up to 128 primary partitions.

Using fdisk for MBR #

fdisk is a common utility for partitioning MBR disks.

# Start fdisk on /dev/sdx (replace 'x' with your device letter)
sudo fdisk /dev/sdx

Within fdisk, you can use:

  • m to display the menu of commands.
  • n to create a new partition.
  • d to delete a partition.
  • w to write changes to disk.

Using gdisk for GPT #

gdisk functions similarly to fdisk but is used for GPT disks.

# Start gdisk on /dev/sdx
sudo gdisk /dev/sdx

Commands in gdisk are similar to fdisk.

3. Creating File Systems #

After partitioning the disk, the next step is creating a file system.

Common File Systems #

  • ext4: mkfs.ext4
  • xfs: mkfs.xfs
# Create an ext4 file system on partition /dev/sdx1
sudo mkfs.ext4 /dev/sdx1

# Create an xfs file system on partition /dev/sdx2
sudo mkfs.xfs /dev/sdx2

4. Mounting File Systems #

To use the file systems, they must be mounted.

# Create a mount point
sudo mkdir /mnt/data

# Mount the file system
sudo mount /dev/sdx1 /mnt/data

Automating Mounts with /etc/fstab #

To ensure the file system is mounted on boot, add an entry to /etc/fstab.

# Example /etc/fstab entry
/dev/sdx1    /mnt/data    ext4    defaults    0    2

5. Managing Logical Volumes (LVM) #

LVM allows for flexible volume management.

Creating Physical Volume #

sudo pvcreate /dev/sdx1

Creating Volume Group #

sudo vgcreate vgdata /dev/sdx1

Creating Logical Volume #

sudo lvcreate -n lvdata -L 10G vgdata

Creating File System on Logical Volume #

sudo mkfs.ext4 /dev/vgdata/lvdata

Mounting Logical Volume #

sudo mkdir /mnt/lvdata
sudo mount /dev/vgdata/lvdata /mnt/lvdata

Conclusion #

Understanding and managing local storage is crucial for system administrators. This tutorial covered the basics of disk partitioning, file system creation, and logical volume management on Red Hat Enterprise Linux. For the RHCSA exam, ensure you practice these tasks until you are comfortable with both the commands and concepts. Remember, hands-on experience is invaluable when preparing for Red Hat certifications.