On 11/11/2016 12:13 PM, The Wanderer wrote:
On 2016-11-11 at 12:37, Christian Seiler wrote:Hi, Am 11. November 2016 17:57:27 MEZ, schrieb Andy Smith <andy@strugglers.net>:Hi Richard, On Fri, Nov 11, 2016 at 10:49:37AM -0600, Richard Owlett wrote:I was considering using dd to copy the entire drive to a *SINGLE* partition of a 1 TB drive with the intention making a "byte perfect" of of the defective drive to a new 300 GB drive at a later time to then attempt "data rescue". Partitions other than the first are evidently readable. Suggestions/comments please.You are better off using GNU ddrescue for taking images of possibly-failing devices.Full ACK: GNU ddrescue has saved my data multiple times in the past, I can really recommend it. (The "log file" is very helpful with resuming at a later point in time if you had to cancel it.) Just don't confuse it with dd_rescue, which I don't recommend unless you are an expert and have a very special case.There's also myrescue, which is similar in function to both but which I've found easier and less confusing to use in the past - if perhaps only because it eliminates the confusion about remembering which of the other two is the one which is more problematic.
http://myrescue.sourceforge.net/ doesn't indicate whether it will attempt to do what I want. https://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html is long and not oriented to first time user. But explicitly claims to do what I want. I'll have to re-read after a good night's sleep.
The trouble with all of these is that not only do you need a device with enough space to store the entire device you're drawing from (ideally in a file rather than on the device directly), to do it properly and safely you also need enough extra space - on another device is fine - to store the log file which gets created during the rescue process.
How big might the logfile be when trying to recover a known flaky 300 GB drive. I've lots of space? Some convienient, some not.