On 05/08/2015 at 07:33 PM, German wrote: > On Fri, 08 May 2015 19:20:37 -0400 > The Wanderer <wanderer@fastmail.fm> wrote: > >> On 05/08/2015 at 07:08 PM, German wrote: >>> That's what I got: >>> >>> spore@asterius:~$ lsblk >>> NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT >>> sda 8:0 0 119.2G 0 disk >>> ├─sda1 8:1 0 512M 0 part /boot/efi >>> ├─sda2 8:2 0 111.3G 0 part / >>> └─sda3 8:3 0 7.4G 0 part [SWAP] >>> sdb 8:16 0 465.8G 0 disk >>> sdc 8:32 0 1.8T 0 disk /media/spore/9F86-0131 >>> sdd 8:48 0 1.8T 0 disk >>> └─sdd1 8:49 0 1.8T 0 part >>> >>> Where sdd is my failed drive. sdc is my spare drive. The correct >>> procedure will be ddrescue if=/dev/sdd1 of=/dev/sdc ? >> >> No. That might potentially work (except that, if I'm reading the >> ddrescue man page correctly, the syntax is wrong), but it wouldn't be >> correct. >> >> First, unmount /dev/sdc. Note for the record: The other steps will erase any data which is presently on /dev/sdc. I figure you probably already know that, but I just want to be explicit about it. >> Then do one of two things: >> >> 1) Create /dev/sdc1 (as an unformatted partition, using fdisk or >> parted or whatever partitioning tool you choose), and then run >> >> ddrescue /dev/sdd1 /dev/sdc1 /any/path/you/want/ddrescue.log >> >> 2) run >> >> ddrescue /dev/sdd /dev/sdc /any/path/you/want/ddrescue.log > > Ok, I think I am getting closer. How big is a log file? The size of the log file depends on two things: the size of the data source which is being copied/rescued, and the number of errors which occur while attempting to read that data source. It can be very small, or it can be moderately large. Even in a ridiculous case, however, I wouldn't expect it to be more than a few hundred megs - unless the source drive is so bad that you're not going to be getting any data back off of it anyway. > Can it be anywhere on all drives that have enough space? For > instance: > > ddrescue /dev/sdd /dev/sdc /dev/sda2/ddrescue.log will work? Not quite. /dev/sda2/ is not a directory; it's a device node. Since /dev/sda2 is mounted to / (the root filesystem), the correct equivalent to this command would be: ddrescue /dev/sdd /dev/sdc /ddrescue.log and although I wouldn't advise storing a log file in the root directory, the command should work. The log file itself can be placed in any writable location which has enough space. -- The Wanderer The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. -- George Bernard Shaw
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