Debug Storage Consumption

In some cases, you may notice that your storage space is being consumed rapidly. This can be due to various reasons such as log files, cache files, or other temporary files. In this guide, we will show you how to debug storage consumption on your server.

Understand Linux disk layout

In Linux, disks are represented as files under the /dev directory. You can use the ls command to list the contents of the /dev directory.

To list all the disks on your system, you can use the following command:

sudo ls /dev/

You can also use the fdisk tool to list all the disks on your system:

sudo fdisk -l

In Linux, all folders and files are stored under the root directory /. There is nothing like D: or E:. All disks are mounted under the root directory as folders. You can use the lsblk command to list all the block devices on your system:

sudo lsblk

If you unplugged a disk from your system, you will notice it disappeared from the output of the lsblk command and fdisk -l command.

Formatting and mounting a disk

If you have a new disk that you want to use, you need to format and mount it. To format a disk, you can use the mkfs command. For example, to format a disk /dev/sdb as ext4, you can use the following command:

sudo mkfs.ext4 /dev/sdb

To mount your new disk, you need to create a mount point and mount the disk to that mount point. For example, to mount the disk /dev/sdb to the /mnt/data directory, you can use the following commands:

sudo mkdir /mnt/data

After creating the mount point, you can mount the disk to that mount point:

sudo mount /dev/sdb /mnt/data

If you want to unmount the disk, you can use the following command:

sudo umount /mnt/data

However, after rebooting your system, the disk will be unmounted. To mount the disk automatically after reboot, you need to add an entry to the /etc/fstab file. For example, to mount the disk /dev/sdb to the /mnt/data directory automatically after reboot, you can add the following entry to the /etc/fstab file:

sudo vim /etc/fstab

You need to add a new line to the /etc/fstab file with the following format:

/dev/sdb /mnt/data ext4 defaults 0 0

The text above will tell the system to mount the disk /dev/sdb to the /mnt/data directory with the ext4 filesystem and default options.

In Linux, best practice before writing to a disk is to check the disk mount point. You can use the df command to check the disk mount point. For example, to check the mount point of the /mnt/data directory, you can use the following command:

cd /mnt/data
df . -Th

If you unplugged a disk from your system, you will notice it disappeared from the output of the df command. However, the mount point will still be there. And you may notice an empty folder with the same name as the mount point.

So always be careful when writing to a disk. If you write to a disk that is not mounted, you will be writing to the mount point folder, which is not what you want.

Check Disk Usage

In some cases, you might notice that your storage space is being consumed rapidly. This can be due to various reasons such as log files, cache files, or other temporary files. In this guide, we will show you how to debug storage consumption on your server.

Before starting, you need to locate the folder which you want to investigate.

cd /var/log

You can use the du command to check the disk usage of a specific folder. For example, to check the disk usage of the /var/log folder, you can use the following command:

sudo df . -Th

You can also use the du command to check the disk usage of a specific folder. For example, to check the disk usage of the /var/log folder, you can use the following command:

sudo du -d 1 -h

The -d 1 option tells the du command to show the disk usage of the first level of the folder. The -h option tells the du command to show the disk usage in human-readable format.

sudo du -d 1 | sort -nr

If you want to sort the output by disk usage, you can use the sort command with the -nr option. The -n option tells the sort command to sort the output numerically, and the -r option tells the sort command to sort the output in reverse order.

And finally, if you found a folder that is consuming a lot of storage space, and you confirmed that the content inside that folder is not important, you can delete that folder using the rm command. For example, to delete the /var/log/some-specific-folder folder, you can use the following command:

sudo rm -rf /var/log/some-specific-folder

That's it! You now know how to debug storage consumption on your server. You can use the du command to check the disk usage of a specific folder and the rm command to delete unnecessary files and folders.