How to Check Bad Sectors or Bad Blocks on Hard Disk in Linux

It doesn’t matter which type of device you’re using; there is
always a chance to get your device damaged. Either it can be
physical damage or logical damage. In most cases, physical errors
occur inside the hard disk of your system. Logical errors occur in
RAM or other components that include a transistor. Bad blocks or
bad sectors occur when you can’t read or write any data on your
hard disk in your Linux system. You shouldn’t get relaxed if you’re
using a Solid-state drive (SSD). Sometimes logical errors are also
seen on SSD. Bad blocks can be the cause of losing all your data
from the hard disk or SSD. That’s why to prevent losing your
valuable data; it’s essential to check if there are any bad sectors
or bad blocks on your hard disk in the Linux system.

Bad Sectors or Bad Blocks on Hard
Disk

Heat, dust, overclocking, unstable power supply, and
partitioning in an improper way can be the reason for having bad
blocks on your hard disk. Depending on how badly your hard disk is
affected, damages can vary over time. Linux maintains a file system
hierarchy, so to check the bad sectors on your hard disk, it is
essential to find out the damage source.

For a hard disk, damages can occur inside the platter,
read-write head, or the actuator arm can be displaced. For SSD’s
damage can be either inside the NAND flash memory or in the host
interface. In this post, we will know why the bad blocks or bad
sectors occur on a hard disk and how to check the bad sectors in
Linux.

Method 1: Use
badblocks Tool to Check Bad Blocks on Hard Disk in
Linux

Using the badblock tool^[1]
in your Linux terminal, you can find out the overall status of your
hard disk. It will take a while to generate a full-body report.
This terminal command can get the read-only permission, so it will
not perform the data writing test. You can choose which partition
of the hard disk device you want to check inside your command
line.

$ sudo badblocks -sv -b 512 /dev/sda
$ sudo badblocks -s /dev/sda

If you want to get an automatically generated log file of all
the bad sectors of your hard disk or storage system, you may try
the badblock CLI written below. This command will generate a text
file inside your directory if bad sectors are found.

$ sudo badblocks -v /dev/sda > badsectors.txt

For fixing the bad sectors from your hard disk, you can run this
command line in your Linux terminal at your own risk. There is a
chance to get your data erased. So, if you’re not an expert, don’t
do it by yourself. Usually, e2fsck^[2]
command can determine superblocks, bad blocks, block sizes, and a
debugging method to rescue the hard disk.

$ sudo e2fsck -l badsectors.txt /dev/sda

Method 2: Monitor
Bad Sectors on Hard Disk Using fdisk list
Command in Linux

Before you check if there are any bad sectors inside your hard
disk, you may need to get a list of all your storage devices that
are connected with your Linux system. To get a display of connected
hard disk/storage devices, you can always run the list command from
your system terminal. Don’t forget to use the terminal as a
superuser. Otherwise, your access can be denied.

$ sudo fdisk -l

Then it’s time to run a combing operation inside your Linux
machine to find all the corrupted blocks of the hard disk. 
Let, we want to save the report card file in the temp directory. In
that case, our CLI will be as exactly shown below. Here, the
-v(visual) is will also display the progress of work
in the terminal. Here, we are trying to find bad blocks of our
sda disk; you will put your desired disk
partition.

$ sudo badblocks -v /dev/sda > /tmp/bad-blocks.txt

Method 3: Check Bad Blocks on Hard
Disk Using smarttools Command in
Linux

Smartmontools^[3]
is a fundamental and neat disk report card tool for Linux that
allows users to generate version, copyright, license, and health
information. To install Smartmontools, follow the given terminal
commands below.

$ sudo apt update
$ sudo apt install smartmontools

After the installation is done, you can now use the
Smartmontools from the terminal in Linux. To get a self-generated
smart report instantly on your display, use the
smartctl command. Don’t forget to mention your hard
disk partition.

$ sudo smartctl -a /dev/sda

To check the overall test report of your hard disk, scroll below
down in your terminal. You will find a full report card that
includes the hard disk device model, serial number, firmware
version, form factor, and most importantly, whether your hard disk
has passed the overall-health self-assessment test or not!

Method 4: Check Hard Disk
Assessment from Linux GNOME Disk Management
Utility

Besides all the methods described above, there is also a quick
method in Linux that allows you to check the current condition,
temperature, cycle count, power-on hours, and an Overall Assessment
of your hard disk. In Linux, for partition editing tasks, most
users are very fond of using Gparted^[4]. Indubitably Gparted is
a great tool.

But apart from all the disk management utility tools^[5], Linux comes with the
default disk management utility for GNOME, named Disk! To get your
hard disk information and status form Disk, open the Disk from your
Linux system panel. After the Disk is opened, click on the
three-dot menu and select the Smart data and self-test
menu.

Here you go! You will be able to see a window like the given
picture below. You will find the Start self-test
button at the bottom of the window. Once you click the self-test
button, it will be started, and after a while at the top right of
the window, you’ll get the Overall Assessment report
of your hard disk.

If you’re still curious, you can check the benchmark report of
your hard disk from your Linux system. Same procedure as we’ve done
just before, from the three-dot menu of GNOME Disk management
utility select the Benchmark Disk, then click on
Start Benchmark. You will see a benchmark graph report
on your Linux display.

Final Thoughts

Rough use of a desktop can interrupt the data processing (read
or write) inside the hard disk. Sudden powering off your machine
can also damage the hard disk. Before taking your hard disk in life
support, regular check-ups can save the life of your hard disk. In
this post, we have explained some common errors that can occur in
your hard disk and also demonstrated several methods of how to
check the bad sectors or bad blocks in the Linux system.

If you’re not a crazy system administrator, of course, you love
your data. Share this post among your Linux user community and also
do comment if you want to ask or add anything related to this
post.