Fixing File System Errors When fsck Fails

Sometimes when fsck runs during startup, it encounters an error that prevents the system from fully booting until you fix the issue by running fsck manually. This error might occur when Photon OS is the operating system for a VM running an appliance.

If fsck fails when the computer boots and an error message says to run fsck manually, you can troubleshoot by restarting the VM, altering the GRUB edit menu to enter emergency mode before Photon OS fully boots, and running fsck.

Perform the following steps:

1. Take a snapshot of the virtual machine.

2. Restart the virtual machine running Photon OS.

   When the Photon OS splash screen appears as it restarts, type the letter e quickly to go to the GNU GRUB edit menu.

   Note: You must type e quickly as Photon OS reboots quickly. Also, in VMware vSphere or VMware Workstation Pro, you might have to give the console focus by clicking in its window before it will register input from the keyboard.

3. In the GNU GRUB edit menu, go to the end of the line that starts with linux, add a space, and then add the following code exactly as it appears below:

   systemd.unit=emergency.target

4. Type F10.

5. In the bash shell, run one of the following commands to fix the file system errors, depending on whether sda1 or sda2 represents the root file system:

   e2fsck -y /dev/sda1

   or

   e2fsck -y /dev/sda2

6. Restart the virtual machine. If the virtual machine fails to boot and finds any error then follow the steps below to recover.

7. Log in to the root shell: Command>shell root@vc701-w4#

8. To know about the error, execute the following command: journalctl -b 0 | grep -i “failed to start”

   Below is output of above command:

9. Referring to the Failed to start the file system check on /dev/log_vg/log error in the screenshot above, if the partition type is logical volume, then the device mapper modules create a device-special file /dev/dm-X to which symbolic links with the original names points to /dev/mapper/log_vg-log or /dev/log_vg/log. Here log_vg is volume group and log is logical volume name.

10. Execute the lsblk command to confirm the device type. Below is the output of lsblk command. Here log_vg-log is associated with the device sde and type lvm. Also, note that it is not mounted.

11. Execute the following command to fix the file system errors: e2fsck /dev/log_vg/log

12. Restart the virtual machine.