[SOLVED] dd, ddrescue and bad blocks...

masavini · 01-09-2016, 05:35 PM

hi,
i have a couple of disks wich are ok, but with a few fixed (marked) bad blocks.

what happens if i use them as target disks of a cloning process (using dd or ddrescue)?

will dd or ddrescue be aware of the marked bad sectors?

thanks!

rknichols · 01-09-2016, 07:14 PM

How are those sectors marked bad? With any modern disk (last decade, at least), any write to a bad sector would cause the drive to reallocate that space to a spare sector. Such a reallocation is transparent to the OS, which sees a fault-free disk. Only the drive's SMART attributes would reveal that anything had happened.

masavini · 01-10-2016, 03:59 PM

so, if i got it properly, once the bad sectors are marked with fsck there is no risk they can be "unmarked", right?

rknichols · 01-10-2016, 04:15 PM

As soon as they are written to, they will no longer be "bad" as seen from the OS. The drive itself will take care of that.