UNIX for Dummies Questions & Answers

Dear List,

While I was adding second hard disk to my system, I changed the /etc/fstab file by adding the following line:

/mnt/sdb1 /dev/sdb1 ext3 default 2 1

Now system does not boot and gives the following error:

Checking filesystems
/: Clean, 309260/18495840 files, 1064776/18486790 blocks
fsck.ext3: Is a directory while trying to open /mnt/sdb1
/mnt/sdb1:
The superblock could not be read or does not describe a correct ext2 filesystem. If the device is available and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8198 <device>
***An error occurred during the filesystem check.
***Dropping you to a shll; the system will reboot
***when you leave the shell.
Give root password for maintenance (or type Control-D to continue):

I was wondering how I can fix this problem. It looks like that I can not change the content of the fstab file because when I give the password and go to the command prompt, I am not able to edit the file or do any changes because it is read-only.

Regards,
Siavoush

The problem is a Linux-idiot-proof method of assigning SCSI disk IDs... it does so in reverse order. So what was sda is now sdb and what you added is probably sda. There are several fixes for this, but first to get your system to boot, you should burn a "rescue CD" and boot from it, manually mount what was originally your root partition, and change the fstab file so that the mountpoints match the new SCSI letter designations.

There are two general ways of fixing this problem. One is to assign a "label" to each filesystem and change fstab to mount these filesystem labels. The other method is to configure the udev scripts so that a particular disk UUID gets mapped to a particular drive letter.

I'll wave my hands professorally, but if you need further help, just follow up.

Ah! Yes, the boot failed in this stage, and all you need to do is remount the root device with:

Code:

mount -o remount,rw /

Then you should be able to edit the fstab file. Should prevent you from needing a rescue disk!