Some common disk errors are physical failures, bad sectors or bad blocks, and inconsistent filesystems. These disk errors can be checked using standard tools in Linux from the command line.

The disk must not be mounted when performing these tests. In the case where it's a root filesystem, and it's not possible to be unmounted when users are logged in, you can use a live Linux system such as by booting into Ubuntu installer disk. It is similar to when recovering a lost partition table.

How to recover lost partition using Linux

Steps to check for disk error and bad sector in Linux:

  1. Launch terminal.
  2. List available disks on your system. 

    $ lsblk NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT loop0    7:0    0 55.4M  1 loop /snap/core18/1997 loop1    7:1    0  219M  1 loop /snap/gnome-3-34-1804/66 loop2    7:2    0 64.8M  1 loop /snap/gtk-common-themes/1514 loop3    7:3    0 32.3M  1 loop /snap/snapd/11588 loop4    7:4    0   51M  1 loop /snap/snap-store/518 loop5    7:5    0 65.1M  1 loop /snap/gtk-common-themes/1515 sda      8:0    0   20G  0 disk  ├─sda1   8:1    0    1M  0 part  ├─sda2   8:2    0  513M  0 part /boot/efi └─sda3   8:3    0 19.5G  0 part / sdb      8:16   0   20G  0 disk /mnt/data sr0     11:0    1 1024M  0 rom

  3. Make sure the disk you want to check is not mounted. 

    $ sudo umount /dev/sdb [sudo] password for user:

  4. Check disk S.M.A.R.T. health status using smarctl. 

    $ sudo smartctl -H /dev/sdb smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.11.0-16-generic] (local build) Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org  === START OF READ SMART DATA SECTION === SMART Health Status: OK

    Related: How to check disk health status in Linux

  5. Check for filesystem consistency of disk using fsck. 

    $ sudo fsck /dev/sdb fsck from util-linux 2.36.1 e2fsck 1.45.7 (28-Jan-2021) /dev/sdb: clean, 11/1310720 files, 126322/5242880 block

  6. Check for disk bad blocks or bad sector using badblocks. 

    $ sudo badblocks -v /dev/sdb Checking blocks 0 to 20971519 Checking for bad blocks (read-only test): done                                                  Pass completed, 0 bad blocks found. (0/0/0 errors)