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Linux gives you granular control over storage at every level — from individual partitions to logical volume groups that span multiple physical disks. Whether you are diagnosing a full filesystem, adding a new data drive, or setting up a flexible LVM layout for a server, the tools you need are all available from the command line. This guide walks through disk inspection, partitioning, formatting, mounting, and LVM management.

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Checking Disk Usage

Before making any changes to storage, understand how your current space is being used. 
df -h                                # disk space (human-readable)
df -h /                              # root filesystem only
df reports usage at the filesystem level — it tells you how much space is available on each mounted volume.

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Listing Block Devices

Get a clear picture of the physical disks and partitions attached to your system before making any changes. 
lsblk                                # tree view of disks
lsblk -f                             # with filesystem info
blkid                                # UUIDs and filesystem types
fdisk -l                             # detailed partition table
lsblk gives a clean tree view that shows how partitions, LVM volumes, and RAID arrays relate to one another. blkid is the quickest way to find a partition’s UUID, which you’ll need for /etc/fstab entries.

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Partitioning with fdisk

fdisk is an interactive tool for creating and managing partitions on MBR-style disks. Identify your target disk with lsblk first.
Partitioning and formatting are destructive operations. Any existing data on the target partition or disk will be permanently lost. Double-check your device path before proceeding — /dev/sdb and /dev/sda are easy to confuse.
sudo fdisk /dev/sdb
# Inside fdisk:
# p - print partition table
# n - new partition
# d - delete partition
# t - change partition type
# w - write and exit
# q - quit without saving
No changes are written to disk until you press w. If you make a mistake, press q to quit without saving and start over.

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Formatting Filesystems

After partitioning, format each partition with a filesystem before you can store data on it. 
sudo mkfs.ext4 /dev/sdb1             # ext4
sudo mkfs.xfs /dev/sdb1              # XFS
sudo mkswap /dev/sdb2                # swap
sudo swapon /dev/sdb2

ext4

The default filesystem for most Linux distributions. Reliable, well-supported, and a safe choice for general-purpose data storage.

XFS

Performs well at large scale and with large files. Common on RHEL/CentOS and used heavily in enterprise environments.

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Mounting Drives

Mount a formatted partition to a directory to make it accessible. 
sudo mount /dev/sdb1 /mnt/data
sudo umount /mnt/data
sudo mount -a                        # mount all in /etc/fstab
Mounts made with mount do not persist across reboots. To make a mount permanent, add it to /etc/fstab. Use the partition’s UUID rather than its device path, as device paths like /dev/sdb1 can change between reboots. 
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx  /mnt/data  ext4  defaults  0  2
Get the UUID for your partition by running blkid /dev/sdb1. After editing /etc/fstab, run sudo mount -a to verify the entry is valid before rebooting.

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LVM: Logical Volume Management

LVM adds a flexible abstraction layer between physical disks and filesystems, letting you resize volumes, add disks to a pool, and take snapshots without downtime.
1

Create physical volumes

Initialize one or more disks or partitions as LVM physical volumes:
sudo pvcreate /dev/sdb
pvdisplay
2

Create a volume group

Group one or more physical volumes into a single storage pool called a volume group:
sudo vgcreate datavg /dev/sdb
vgdisplay
3

Create logical volumes

Carve logical volumes out of the volume group. Each logical volume behaves like a partition that you can format and mount:
sudo lvcreate -L 50G -n datalv datavg
lvdisplay
4

Extend a logical volume

When you need more space, extend the logical volume and resize the filesystem — no unmounting required for ext4:
sudo lvextend -L +10G /dev/datavg/datalv
sudo resize2fs /dev/datavg/datalv    # resize ext4 filesystem
For GPT partition tables — required for disks larger than 2 TB — use parted instead of fdisk. The parted command supports GPT natively and can also resize partitions non-destructively in some cases.