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Disk Partitions: Dividing Your Disk

Partitions divide disks into sections. Like rooms in a house.

Here's the thing: You'll rarely create partitions. But you need to understand them. They organize storage.

What Partitions Are​

Partitions divide physical disks into logical sections:

  • Separate operating systems
  • Organize data
  • Improve performance
  • Enhance security

My take: Most systems have partitions already. You usually don't need to create them.

Viewing Partitions​

lsblk: List Block Devices​

lsblk                             # List all devices
lsblk -f                          # Show filesystems

Output:

NAME   SIZE TYPE MOUNTPOINT
sda    20G  disk
├─sda1 512M part /boot
└─sda2 19.5G part /

My take: lsblk shows partitions. Use it to see disk layout.

fdisk: Partition Table​

sudo fdisk -l                     # List all partitions
sudo fdisk -l /dev/sda            # Specific device

My take: fdisk -l shows detailed partition information.

Common Partition Layout​

Typical setup:

  • /boot = Boot files (small, ~500MB)
  • / = Root filesystem (most space)
  • /home = User data (optional, separate)
  • /var = Variable data (optional, separate)

My take: Most systems have /boot and /. That's enough. Separate partitions are optional.

Creating Partitions (Advanced)​

fdisk: Interactive Editor​

sudo fdisk /dev/sda               # Edit partition table

Commands:

  • p = Print partition table
  • n = New partition
  • d = Delete partition
  • w = Write and exit
  • q = Quit without saving

My take: fdisk is interactive. Be careful. Wrong commands can destroy data.

parted: Advanced Tool​

sudo parted /dev/sda              # Interactive mode
sudo parted /dev/sda print         # Print partitions

My take: parted is more advanced. Use fdisk for basic needs.

When You Need Partitions​

You'll create partitions when:

  • Installing Linux
  • Adding new disk
  • Reorganizing storage
  • Setting up dual boot

My take: Most of the time, partitions already exist. You don't need to create them.

Common Mistakes (I've Made These)​

  1. Deleting wrong partition: Partitions contain data. Deleting loses data. Be careful.

  2. Not writing changes: fdisk changes aren't saved until you write. Use w to save.

  3. Wrong device: Make sure you're editing the right device. Check with lsblk.

  4. Not backing up: Partition changes can't be undone. Backup first.

  5. Creating too many partitions: Keep it simple. Most systems don't need many partitions.

Real-World Examples​

View Partition Layout​

lsblk -f

Check Partition Usage​

df -h

Add New Disk​

# 1. Attach disk
# 2. Create partition
sudo fdisk /dev/sdb
# 3. Format
sudo mkfs.ext4 /dev/sdb1
# 4. Mount
sudo mount /dev/sdb1 /mnt/data

What's Next?​

Now that you understand partitions, let's talk about Filesystems to format them.

Personal note: When I started, I thought partitions were complex. Then I realized: most systems already have them. You rarely need to create them. Understand them. But don't overthink them.