Recover failed HDD using Open Source tools

This will show how to recover failed hard disk using Linux and open source tools

Failed hard disk in this case means:

• S.M.A.R.T. not healthy.
• Hard disk have some bad sector
• Some data cannot read and make system slow
• The disk are still available in /dev/

The tools

• Ubuntu Linux or other GNU Linux
• GNU ddrescue

Process:

• install the tools

# apt-get install gddrescue smartmontools

• Plug your failed hdd to linux system, use dmsg | tail to determine what device name were shown in this case is sdb ( /dev/sdb )
• If you want to recovery whole drive to another new healthy disk (disk to disk), 
• # ddrescue -f -n /dev/sdb /dev/sdX logfile.log # where X is your new healthy disk
• The option -f and -n said force dump "only" the good parts from your failed hdd to new one, this will skip the error parts and make this activity faster than the dd command.
•  ddrescue use logfile.log file next time for recover the error parts.
• Now the error parts.
• # ddrescue -d -f -r3 /dev/sdb /dev/sdX logfile.log # where X is your new healthy disk
•  The option -r3 said try 3 times to read error parts, you can change the desire value depends on your hdd health.
• You may or may not check your  new disk (fsck) when finish.

Summary and suggestion:

• Always monitor your hard disk health, use smartmontools and setup the daemon will help.