Problem: When you get I/O errors on your computers hard disk, it’s usually urgent to copy all data to a new disk. If you try to do a 1:1 copy using dd, you will see that dd stops when it reaches the first bad sector.
Solution: use the following command to copy from one hard disk to second hard disk, with every bad sector replaced with an all zero sector on the target hard disk
dd if=/dev/sda of=/dev/sdb conv=noerror,sync
With “/dev/sda” as source disk and “/dev/sdb” as destination disk. You can add “bs=4096” or higher to speed up the copy process.