How to check bad sectors in hard disk

This article will explain how to check bad sectors in hard disk using in Linux dedicated server.

Let us start by defining a bad sector/block, it’s a section on a disk drive or flash memory that can not be read from or written to anymore, as a result of a fixed physical damage on the disk surface or failed flash memory transistors.

As bad sectors continue to accumulate, they can undesirably or destructively affect your disk drive or flash memory capacity or even lead to a possible hardware failure.

It is also important to note that the presence of bad blocks should alert you to start thinking of getting a new disk drive or simply mark the bad blocks as unusable.

Therefore, in this article, we will go through the necessary steps that can enable you determine the presence or absence of bad sectors on your Linux disk drive or flash memory using certain disk scanning utilities.

That said, below are the methods:

Methods to check bad sectors in hard disk

1. Using smartctl (S.M.A.R.T. Monitoring)

The smartctl tool is used to interact with the S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) system, which can help you detect issues with your hard drive, including bad sectors.

Steps:

1.Install smartmontools (if not already installed):

sudo apt-get install smartmontools # For Debian-based systems
sudo yum install smartmontools # For RHEL-based systems
sudo pacman -S smartmontools # For Arch Linux

2.Check the health status of your disk:

sudo smartctl -a /dev/sdX

Replace /dev/sdX with the actual device name of your disk, such as /dev/sda or /dev/sdb.

The output will show various attributes of the disk, including any “Reallocated Sectors” or “Pending Sectors,” which are indicators of bad sectors.

3.Run a Self-Test (optional): To run a basic short test to check for issues, use:

sudo smartctl -t short /dev/sdX

After the test finishes, you can view the results:

sudo smartctl -a /dev/sdX

2.Using badblocks

The badblocks utility is specifically designed to scan and identify bad sectors or blocks on a disk.

Steps:

    1.Run the badblocks command: To scan the disk for bad sectors (replace /dev/sdX with your disk name):

sudo badblocks -v /dev/sdX

The -v option makes the command output more verbose, showing progress.

To write the results to a file:

sudo badblocks -v /dev/sdX > badblocks.txt

      2.Non-destructive Test (read-only): You can perform a read-only test to check for bad blocks without modifying the disk:

sudo badblocks -n -v /dev/sdX

This test won’t attempt to repair any bad blocks but will help in detecting them.

3. Using fsck (File System Check)

If you’re experiencing file system issues that might indicate bad sectors, running a file system check with fsck can help identify and sometimes fix them.

Steps:

1. Unmount the disk (if it’s mounted):

sudo umount /dev/sdX1 # Replace with your specific partition (e.g., /dev/sda1)

      2.Run fsck on the partition:

sudo fsck /dev/sdX1

This will check the file system for errors, including bad sectors. You can pass the -c option to fsck to run badblocks during the file system check, which helps to detect bad sectors:

sudo fsck -c /dev/sdX1

4.Using hdparm (Disk Health)

hdparm can give you an overview of the disk’s health, although it is less detailed than smartctl.

Steps:

    1.Install hdparm (if not already installed):

sudo apt-get install hdparm # For Debian-based systems
sudo yum install hdparm # For RHEL-based systems
sudo pacman -S hdparm # For Arch Linux

     2.Check for health status:

sudo hdparm -I /dev/sdX

This will show information about the drive, including whether it reports any errors or bad sectors.

5.Using dmesg (System Logs)

Sometimes bad sectors or disk issues will be reported in the system logs. You can check the dmesg log for related messages.

Steps:

      1.View disk-related messages:

dmesg | grep -i error

Look for messages related to your disk (/dev/sdX) that indicate problems, like I/O errors, read/write errors, or sector reallocation.

Conclusion

To check bad sectors in hard disk Linux, tools like smartctl, badblocks, fsck, and hdparm are your best options. Using smartctl and badblocks for a deep scan, along with fsck for file system-level checks, can help ensure that your disk is in good health.

From the above you can know how to bad sectors in hard disk in simple ways.