RHCSA Storage Management & Disk Operations

CloudNetOps

CloudNetOps

— 3 min read
Expertise in Cloud, Networking & DevOps
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📌 Introduction

Storage management is a fundamental aspect of system administration, ensuring efficient data organization, performance, and scalability. The RHCSA exam tests knowledge of Logical Volume Management (LVM), mounting storage, and NFS integration. This guide provides a hands-on approach to mastering these skills.

📖 What You’ll Learn in This Guide

🔹 Creating, managing, and resizing LVM volumes

🔹 Mounting and configuring storage devices

🔹 Setting up and troubleshooting NFS (Network File System)

🔹 Optimizing and monitoring disk usage

🛠 Logical Volume Management (LVM)

1️⃣ Understanding LVM Components

LVM provides flexibility in managing storage. It consists of:

  • Physical Volume (PV): Physical disk or partition
  • Volume Group (VG): Group of PVs pooled together
  • Logical Volume (LV): Virtual partitions created from VGs

2️⃣ Creating an LVM Setup

Step 1: Create Physical Volumes

sudo pvcreate /dev/sdb /dev/sdc  # Initialize disks as physical volumes

Step 2: Create a Volume Group

sudo vgcreate my_vg /dev/sdb /dev/sdc  # Create a volume group from PVs

Step 3: Create a Logical Volume

sudo lvcreate -L 10G -n my_lv my_vg  # Create a 10GB logical volume

Step 4: Format and Mount the LV

sudo mkfs.xfs /dev/my_vg/my_lv  # Format LV with XFS
sudo mkdir /mnt/my_storage  # Create mount directory
sudo mount /dev/my_vg/my_lv /mnt/my_storage  # Mount LV

To make the mount permanent, add this line to /etc/fstab:

/dev/my_vg/my_lv /mnt/my_storage xfs defaults 0 0

🔍 Best Practice: Use lsblk to verify disk layout and mounted partitions:

lsblk -f

🚀 Resizing LVM Volumes

1️⃣ Extending a Logical Volume

Increase the size of an existing LV:

sudo lvextend -L +5G /dev/my_vg/my_lv  # Add 5GB to LV
sudo xfs_growfs /mnt/my_storage  # Resize the filesystem (for XFS)

2️⃣ Reducing a Logical Volume

Reducing LV size (for ext4 file system):

sudo umount /mnt/my_storage  # Unmount LV before resizing
sudo e2fsck -f /dev/my_vg/my_lv  # Check filesystem integrity
sudo resize2fs /dev/my_vg/my_lv 10G  # Resize filesystem first
sudo lvreduce -L 10G /dev/my_vg/my_lv  # Reduce LV size
sudo mount /dev/my_vg/my_lv /mnt/my_storage  # Remount the LV

🔍 Best Practice: Always back up data before resizing a volume.

🔗 Mounting Storage Devices

1️⃣ Listing Available Storage Devices

lsblk -f  # List block devices and file systems
fdisk -l  # View disk partitions

2️⃣ Mounting a New Disk

Step 1: Format the Disk

sudo mkfs.ext4 /dev/sdd  # Format disk with ext4 filesystem

Step 2: Create a Mount Point

sudo mkdir /mnt/data_disk  # Create mount directory

Step 3: Mount the Disk

sudo mount /dev/sdd /mnt/data_disk  # Mount the disk

To make it persistent across reboots, add this to /etc/fstab:

/dev/sdd /mnt/data_disk ext4 defaults 0 0

🔍 Best Practice: Use UUID instead of device names in /etc/fstab to avoid mount failures:

blkid /dev/sdd  # Find the UUID of the device

📡 Configuring NFS (Network File System)

1️⃣ Installing NFS Server

sudo dnf install -y nfs-utils  # Install NFS utilities
sudo systemctl enable --now nfs-server  # Start and enable NFS service

2️⃣ Configuring NFS Exports

Edit /etc/exports and add:

/mnt/nfs_share 192.168.1.0/24(rw,sync,no_root_squash)

Apply changes:

sudo exportfs -arv

3️⃣ Mounting NFS on a Client Machine

Step 1: Install NFS Client

sudo dnf install -y nfs-utils  # Install NFS client utilities

Step 2: Mount the NFS Share

sudo mount -t nfs 192.168.1.100:/mnt/nfs_share /mnt/nfs_client  # Mount NFS share

To make the mount persistent, add this to /etc/fstab:

192.168.1.100:/mnt/nfs_share /mnt/nfs_client nfs defaults 0 0

🔍 Best Practice: Use showmount -e <NFS-server-IP> to verify available exports:

showmount -e 192.168.1.100

🛠 Essential Practice for RHCSA

✅ Create and manage LVM partitions

✅ Mount and format storage devices

✅ Configure persistent storage mounts

✅ Set up and troubleshoot NFS server & client

✅ Optimize disk usage and resize logical volumes

📌 Next Article: RHCSA User & Group Management

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