title: CentOS 6.7 fails to start due to changes in /etc/fstab
body: <p>Apart from the main disk, I used to have another disk attached to the host which is /dev/vdb. In order to mount it automatically, I made changes in the /etc/fstab file.</p>
  
  <p>While after I removed /dev/vdb, my CentOS 6.7 fails to start, and always stops with an error saying /dev/vdb is unavailable.</p>
  
  <p>At this point, I can type the root password to enter into the command prompt, while when I trying to edit /etc/fstab file, it shows it is in read-only mode. I can't understand why it's read-only since I'm already the "root".</p>
  
  <p>I'm sure removing the problematic line from fstab file would resolve my problem, but no idea of how to override the file. Can somebody help me out?</p>