How To Analyse Disk Usage in Ubuntu Ignoring Mounted File Systems

In this article, we will delve deep into the process of analyzing disk usage in Ubuntu while ignoring mounted file systems. This is a crucial task for system administrators and users alike to manage disk space efficiently and understand where and how the storage is being utilized.

Understanding Disk Usage

Disk usage refers to the amount of disk space used by a file or directory on a file system. In Ubuntu, several tools allow you to analyze disk usage, such as du, baobab, and ncdu. However, these tools also include the disk usage of mounted file systems by default, which can skew the results if you’re only interested in the disk usage of the root file system.

Analyzing Disk Usage with Baobab

Baobab is a graphical disk usage analyzer included in the GNOME desktop environment. It provides a visual, intuitive interface to understand disk usage.

To analyze disk usage with Baobab while ignoring mounted file systems, you can mount the root file system in a different location and analyze it. Here’s how:

1. Create a new directory to serve as the mount point:

   mkdir root-rebound

2. Mount the root file system to the new directory:

   sudo mount /dev/sda1 root-rebound

   Here, /dev/sda1 is the device file for the root file system. Replace it with the appropriate device file if your root file system is on a different device.
3. Analyze the mounted root file system with Baobab:

   baobab root-rebound

4. After analyzing, unmount the root file system and remove the temporary mount point:

   sudo umount root-rebound
   rmdir root-rebound

Analyzing Disk Usage with Du

The du (disk usage) command is a standard Unix command used to estimate file and directory space usage. It provides several options to customize the analysis.

The -x or --one-file-system option can be used with du to skip directories on different file systems. This effectively ignores all other mounted file systems:

du -hx

In this command, -h stands for “human-readable”, making the output easier to understand by converting sizes into KB, MB, GB etc. The -x option ensures that du only considers the current file system.

You can also use the --exclude option to exclude specific directories from the analysis. For example, to exclude the /media directory where most file systems are mounted:

du -h --exclude /media

To sort the output of du in ascending order, you can use the sort command:

du -hx | sort -h

Analyzing Disk Usage with Ncdu

Ncdu (NCurses Disk Usage) is a command-line disk usage analyzer with a ncurses interface. It’s not included in Ubuntu by default, but you can install it with:

sudo apt-get install ncdu

To analyze disk usage with ncdu while ignoring mounted file systems, use the -x option:

ncdu -x

Just like with du, the -x option tells ncdu to only consider the current file system.

Conclusion

Analyzing disk usage while ignoring mounted file systems in Ubuntu can be accomplished using various tools such as baobab, du, and ncdu. Each tool has its own strengths and weaknesses, and the choice of tool depends on your specific needs and preferences. With the knowledge of these tools and their usage, you can efficiently manage your disk space and understand where your storage is being utilized.