Linux Plus-Managing Linux Disks and Partitions

Overview

Hardware

• List hardware devices
• Create disk files to act as storage
• List available and used storage

Partitions

• Create and read partition tables
• Encrypt partitions

Listing Hardward and Storage

• -S - based on size
• -r - Display reverse

Alma Linux 8.5

Discover Hardware

• Block device files
• Available disk space
• More options to the ls command

lsblk

• sda - first disk
• sda1 - SWAP - mounting point
• sda2 - / - root filesystem

lspci

lscpu

lsusb

To find the disk space, use df

• -h - human readable

  df -h /
  

  

To find the size of the directory

df -h /etc/services
680K    /etc/services

To find and display the large file size

• S - size of the file
• r - listed in reverse order

  ls -lhSr /etc
  

  

Understanding Disk Files

Working with ISO Files

• Download small ISO and mount it.
• List devices with lsblk and losetup

  yum list wget
  yum provides /usr/bin/wget
  sudo yum install -y wget
  wget https://download.virtualbox.org/virtualbox/4.0.0/VBoxGuestAdditions_4.0.0.iso
  sudo mount VBoxGuestAdditions_4.0.0.iso /mnt
  ls /mnt ; lsblk ; sudo losetup
  sudo unmount /mnt
  

Creating a Disk File

Using either dd or fallocate, we can create disk file. The latter being more efficient as it does not copy the data just allocating space.

• Create disk file with dd
• Create disk file with fallocate

dd if=/dev/zero of=disk1.img bs=1M count=1000
fallocate -l 1G disk2.img

Linking Devices to Files

• Using losetup

Understanding Disk Partitions

Partitioning Disks

• Using the fdisk command
• Using the parted command
• Using partprobe to read partition tables

Encrypting Disks and Partitions Using LUKS

• lsblk - list out the block devices
• dd, fallocate - create raw files and
• losetup - link them to loop devices with losetup
• parted or fdisk - create partitiions
• partprobe - to reread the partition table
• cryptsetup - encrypting a partition or encrypting a disk will encrypting the underlying structure, so any filesystem that is laid upon it is going to be encrypted.