Apologies if this is the wrong place to ask for help. I was directed here after asking this question on the PartedMagic support forum.
A copy of my query (with screenshots of terminal output) can be found here: http://unix.stackexchange.com/questions/219365/ddrescue-recovering-0b-but-drive-appears-in-device-manager-is-it-failing-to-con I have a failing hard-drive from a NAS. First sign of trouble came when the drive showed all its root folders and sub-directories as empty, although windows (via a mounted share) still displayed the expected disk usage, about 1.2TB of the full available 1.8TB). After a bit of research I came across a guide that recommended first making a copy of the disk using ddrescue and trying to recover data from the copy. I purchased PartedMagic and a second 2TB Seagate Barracuda drive to clone to. Running lsblk -o name,label,size,fstype,model confirms the failing drive as sda and the new drive as sdb So I tried ddrescue... initially using: ddrescue -d -f /dev/sda /dev/sdb /media/sdd1/rescue.logfile (where sdd1 is another usb stick attached to the system to save the logfile to) But from the very start, the terminal output shows: 0 B copied, current rate remains at 0B/s and run time and successful read (time) remain identical. In other words, as far as I can tell ddrescue never actually reads a single byte from the failing disk: I let this run for about two days until the Finished prompt appeared in the terminal. 0 B copied. So I then tried partitioning the new drive (with a single ntfs partition, to match the failing drive) and repeated the process but this time only cloning the partition: ddrescue -d -n -f /dev/sda1 /dev/sdb1 /media/sdd1/rescue2.logfile Same result. I also tried copying to a disk image ddrescue -d -n /dev/sda1 /dev/sdb1/drive.img /media/sdd1/rescue3.logfile Again, after ending at the Finished prompt the drive.img file was 0B. I then tried different ddrescue options, reading backwards, with and without direct access, using --force, powering the drive on and off a number of times (cringe!) each time hoping that it would suddenly start being read by ddrescue... no luck. The disk appears in 'Places' with its partition name 'GoFlex Home' so although I know you're not meant to, someone suggested mounting the drive. They'd had a similar 0 B problem and found that mounting the drive in read only mode solved the issue for them. I tried but just got an error telling me there was an i/o error and that the drive probably has a hardware fault and can't be mounted. So... maybe I'm being overly optimistic but I can't see how a drive that is so badly damaged can appear in File Manager with its partition name intact. Why can't ddrescue rescue a single byte scanning either forwards or backwards? I can't quite believe it, I must be doing something wrong but I don't know what else to try and I don't want to further damage the disk unnecessarily. In short, ddrescue completes but recovers 0B although the drive appears in device manager. Is it really that damaged or is ddrescue failing to connect? Other forums have suggested booting to Windows and do CHKDSK and trying sudo dd if=/dev/sda of=./img bs=4k count=4 and see if ./img turns out empty Do any of you with data recovery expertise recommend doing that? Any help or advice would be very much appreciated. Many thanks, Jerome _______________________________________________ Bug-ddrescue mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-ddrescue
