How to check the disk usage on a Linux server

    Checking disk usage on a Linux server is essential to ensure that your system has sufficient storage space for smooth operation. Here’s a step-by-step guide on how to monitor disk usage effectively:

    1. Using the df command

    The df (disk free) command provides a summary of the disk space usage on your server.

    $ df -h

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        50G   15G   30G  32% /
tmpfs           1.9G  1.3M  1.9G   1% /dev/shm
/dev/sdb1       100G   70G   30G  70% /data
    • Filesystem: The name of the disk or partition.
    • Size: Total space available on the disk.
    • Used: Space currently used on the disk.
    • Avail: Space available for use.
    • Use%: Percentage of disk used.
    • Mounted on: Directory where the filesystem is mounted.

    2. Using the du command

    The du (disk usage) command gives you detailed information about disk usage by individual directories and files.

    $ du -sh /path/to/directory

1.5G    /path/to/directory

    The -s option provides a summary, and the -h option makes the output human-readable.

    To check the disk usage of all directories within a specified path:

    $ du -h /path/to/directory

1.5G    /path/to/directory
1.0G    /path/to/directory/subdirectory1
500M    /path/to/directory/subdirectory2

    3. Using lsblk for detailed information

    The lsblk command lists all block devices, including partitions and their mount points.

    $ lsblk

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0   50G  0 disk 
└─sda1   8:1    0   50G  0 part /
sdb      8:16   0  100G  0 disk 
└─sdb1   8:17   0  100G  0 part /data

    This will provide detailed information on the available storage devices, their sizes, and mount points.

    4. Using ncdu for an interactive approach

    ncdu is a disk usage analyzer that provides an interactive interface to explore disk usage in a directory.

    $ ncdu /path/to/directory

--- /path/to/directory -----------------------------------------
    1.5 GiB [##########] /subdirectory1
  500.0 MiB [###       ] /subdirectory2
    1.0 GiB [####      ] /subdirectory3
    2.0 GiB [##########] .

    Install ncdu if it’s not already available:

    $ sudo apt install ncdu   # For Debian/Ubuntu-based systems
$ sudo yum install ncdu   # For CentOS/Red Hat-based systems
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