All operations that modify the image (e.g. After ddrescue finishes I remove write permission from the image, create its copy ( cp -reflink=always …) which initially takes virtually no additional space. I use Btrfs for this even when I don't need compression, because Btrfs supports copy-on-write.

But read the whole current answer before you decide. Please see Uses of single-partition disk configuration.

The filesystem may be in a partition ( /dev/sdc1) or on the entire device ( /dev/sdc). Create a filesystem in the target drive, even without compression, and the image and the mapfile will fit. But in your case of a failing drive this approach is not recommended.įortunately you said (in a comment) that 'the target drive is double the size of the failing one'. If the source drive was healthy, you could do this: Clone only space in use from hard disk. However there is no easy way to tell in advance if data can be compressed/sparsified enough. But even if the target disk is not bigger, a filesystem with compression and/or the -S/ -sparse option of ddrescue may be enough to squeeze the image into the filesystem. This will work well if the target disk is bigger than the source one, so even after the filesystem takes some space for its structures there will be enough room for the image (of the size of the source disk) and the mapfile. Let the mapfile be another regular file in the same filesystem (sane idea: in the same directory). Where do i write the log file (map file) Can I also write that to the new target disk?Ĭreate a filesystem on the target disk, mount it and tell ddrescue to write to a regular file in the filesystem, not to the device ( /dev/sdc in your commands).

Do I have to check if the disk sector sizes are the same and pass any parameters to ddrescue if they're not?.

Do I have to ensure the drives are not mounted before running ddrescue?.

If I had to choose, is it better to have the new drive in the SATA port and the failing drive in the enclosure or vice versa?.

I read it's not a good idea to connect the hard drive to a USB enclosure? What alternative do I have though if I only have one SATA connection?.

Where do I write the log file (map file) if the Ubuntu live USB does not have persistent storage and the other disks are unmounted? Can I also write that to the new target disk? How big is the log file typically?.run ddrescue with a first pass to quickly recover the easy sectors and then run a second passĭdrescue -f -n /dev/sdb /dev/sdc rescue.logĭdrescue -d -f -r3 /dev/sdb /dev/sdc rescue.log.connect the old failing drive via USB enclosure.connect the new target drive via SATA on my computer.boot via Ubuntu live USB and use ddrescue.Providing the /bin/dd_rescue executable.I'm about to start a recovery with ddrescue and was wondering if I'm on the right path with these steps. Please note that this is the dd_rescue version of Kurt Garloff If you are searching for theĭdrescue version of Kurt Garloff please check out the Please note that this is the GNU ddrescue version providing

Unfortunately, the package names in the Ubuntu repositories are confusing dd_rescue is packaged under the name ddrescue, and ddrescue under gddrescue! From the package summaries: One disadvantage of GNU ddrescue is that it doesn't support piped output, which means you can't compress the output image with gzip or lzop. One advantage of GNU ddrescue is that it backs up most data faster, by first skipping bad blocks (hich are slow to recover) and coming back to them only after good blocks have been backed up. It's written in C++ and it's small and fast. It keeps this info in a really simple logfile format, and keeps it updated every 30 seconds, or whenever it stops or is interrupted.

It combines both dd_rescue's ability to read big blocks and then shift gears, with dd_rhelp's ability to remember what parts of the disk have been looked at already. But GNU ddrescue it's far better than both - I've tried all three, on the same drive, as well as trying to use plain old 'dd'.Īntonio Diaz Diaz's GNU ddrescue learned from these experiences. It is modeled after the two preceding programs, dd_rescue (with an underbar), and dd_rhelp. For example,ĭdrescue wins (in my book) because it is an efficient self-contained program written in C++ (not a shell script kludge), produces much cleaner output on the console/terminal, and (most importantly) handles unreadable blocks gracefully and intelligently. Several sources prefer GNU ddrescue over dd_rescue. Garloff's program dd_rescue is the first attempt to improve on dd GNU ddrescue is newer and was created to address shortcomings in dd_rescue. Both have the same purpose and are actively developed. Ddrescue, confusingly, can refer to two completely separate programs, dd_rescue by Kurt Garloff, and GNU ddrescue.

Systemrescuecd dd vs ddrescue