mounting a bad hard drive read-only (like the kernel does during boot)

DeuceNegative · 01-02-2008, 06:03 PM

Hello,

My root filesystem is on a failing hard drive, and I want to backup the data. Normal booting fails at the point when it tries to remount the root filesystem read/write. I can successfully boot into emergency mode, with the root filesystem mounted read-only, and I can browse the filesystem. However, in order to backup some precious files, I would like to use the network and other things that are not available in emergency mode.

So, I would like to load a Knoppix LiveCD, mount my bad drive read-only, copy some important files over the network, and deal with the rest of the drive later. However, when I try to mount the drive with something along the lines of:

Code:

# mount -vi -t reiserfs -o ro,noatime,notail /dev/sda3 /mnt/rescue

it fails, looping with this error about bad blocks:

Code:

ata1: translated ATA stat/err 0x51/40 to SCSI SK/ASC/ASCQ 0x3/11/04
ata1: status=0x51 { DriveReady SeekComplete Error }
ata1: error=0x40 { UncorrectableError }

The same thing happens whether or not I use all those options with mount. I can mount other partitions on the drive without problems.

Given that an emergency mode boot can mount the drive read-only, I'm hoping a LiveCD can also. Does anybody know how?

Thanks!

syg00 · 01-02-2008, 06:21 PM

Try "errors=remount-ro"

DeuceNegative · 01-02-2008, 06:44 PM

Thanks for the help.

Unfortunately, the errors=remount-ro option seems to only be available for ext2, ext3, and jfs. I'm using reiserfs.

Junior Hacker · 01-02-2008, 09:48 PM

If you get yourself the Helix Live CD you can just click on the device icon on the desktop. Because it is a forensics CD, it defaults to mounting in read only mode. It also has a lot of nifty data recovery tools and great documentation.