Topics: Red Hat / Linux, Storage

RHEL: Recovering a corrupt file system in emergency mode

If you have a RHEL system that boots in emergency mode due to a corrupt file system, here are some steps to perform to resolve the issue.

Once booted in emergency mode, connect to the system on the console. Try running:

# journalctl -xe
To help determine why the system booted in emergency mode. For example, you may discover that the /var file system has an issue.

Once you do, shut down the system, and boot it from the boot ISO or DVD (depending if the system is a virtual or a physical system).

When using VMware, you'll have to edit the settings of the VM, and enable the "Force BIOS setup" setting, and mount/connect the boot ISO image. Then start it up, and open the console. Once in the BIOS, make sure CDROM is high in the boot order.

Once the system is booting RHEL, select "Troubleshooting", and "Rescue a Red Hat Enterprise Linux system". The system will boot up. Select "Continue" when prompted.

Run "df -h" to list the mounted directories. Since /var is the file system having the issue, unmount it:
# unmount /mnt/sysimage/var
Once /var is unmounted, run fsck to fix any issues:
# fsck /mnt/sysimage/var
Once completed, you can reboot the system. If you connected an ISO image earlier, make sure to disconnect the ISO image.

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