[TriLUG] Need help with recovering data from a drive

[Steve Litt via TriLUG]

On Sun, 5 Apr 2015 08:57:10 -0700 (PDT)
Joseph Mack NA3T via TriLUG <trilug at trilug.org> wrote:

> On Sat, 4 Apr 2015, Moustapha Barry via TriLUG wrote:
> 
> > I would appreciate anybody's help on this. I believe that the boot
> > record was damaged and that imaging the drive will allow me to
> > recover the data on it. Is there any tool I can use to recover the
> > data on this drive?
> 
> as soon as you have a disk with problem, unpower it. You don't want
> more bad sectors if that is the problem. I assume the drive is not
> dead and not clicking.
> 
> If it is just a boot sector problem, make up a usb grub flash key
> (you should always have grub on at least some of your flash keys for
> when this happens), or download a bootable CD (will be called
> supergrub or something like that).
> 
> if it's a dieing disk problem:
> 
> boot the machine off the systemrescuecd (this can boot another OS too)
> 
> http://www.sysresccd.org/SystemRescueCd_Homepage
> 
> assume your bad disk is /dev/sda unmounted
> 
> assume you have some other disk to copy the bad disk to, mounted
> at /mnt
> 
> run ddrescue in two steps
> 
> ddrescue -n /dev/sda /mnt/sda.rescue /mnt/sda.log
> 
> (do not erase /mnt/sda.log)
> 
> ddrescue -d r3 /dev/sda /mnt/sda.rescue /mnt/sda.log
> 
> by watching the output or reading the log file, you'll know how the
> rescue went.
> 
> you can start messing with the copy (mount it and look inside).
> 
> If there's large numbers of missing sectors, put the disk in the
> freezer. Attach power/data cables to it, wrap it in a single paper
> towel and then in a zip lock (with the cables poking out of the
> corner) and put it in the freezer for an hour or two. Pull the bag
> out and attach the disk in the bag via the cables to your
> systemrescuecd machine. The paper towel inside the bag will prevent
> the disk from condensation from moisture getting in through the gap
> for the cables. Rerun the last ddrescue command. The logfile will
> direct ddrescue to only attempt to recover the missing sectors
> 
> Joe


Nice!!!!!!!

Only thing I can add is that if the data's really important, I use two
known-good disks: One to serve as the backup, and another to work with
and eventually become the replacement.


SteveT

Steve Litt 
Twenty Eight Tales of Troubleshooting
http://www.troubleshooters.com/28