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I've read I should ddrescue my not-booting hard drive in raw to a larger USB drive. I read this GNU ddrescue Manual but I'm sure which command to use, and whether to chose direct disk access or raw? I am a linux newbie.

Currently in progress, estimated time left: 8 days:

ddrescue -f /dev/sda /dev/sdb logfile e2fsck -v -f /dev/sdb mount -t ext2 -o ro /dev/sdb /mnt

Update: I bought a new USB hard drive and use it as target. ddrescue has been running for some hours at 400 kB/s. So it will take more than a week a current pace. The laptop is quite old so I worried the heat accumulation might hurt the drive?

Then I read this another recommendation that I should first do a fast -n before running the slower, thorough method. I wonder if this would still be a useful method, considering 5 GB has been rescued already? ddrescue --no-split (cached reads)

When I installed lubuntu 13.10 I encrypted it with LVM. Then I upgraded to 14.04 when it was released and now it won't boot.

Live CDs can mount the 255MB volume sda1 (boot) but not the sda2 and sd5 partitions.

sudo fdisk -l /dev/sda

which returned among other things:

Device boot - Start - End - Blocks - Id - System /dev/sda1 * - 2048 - 499711 - 248832 - 83 - Linux /dev/sda2 - 501758 - 976769023 - 488133632 - 5 - Extended /dev/sda5 - 501760 - 976769023 - 488133632 - 8e - Linux LVM

For more on the background, see here: How to recover encrypted LUKS lubuntu data?

This ddrescue suggestion also gave me a hint: USB rescue data - ddrescue answer

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  • if you use /dev/sdb as output you will overwrite the device including the partition table. I would save the data you want to keep on /dev/sdb1 elsewhere first, or choose a different existing target for the recovery. I've never had need for the ddrescue switches. just specifying input output and logfile have always worked fine in my experience.
    – Elder Geek
    Oct 18, 2014 at 14:47
  • Ok, I glad I asked before trying that. I don't have enough any free storage to save the sdb1 data anywhere else, so then naming the output folder (see my updated guess) would work?
    – lion7
    Oct 18, 2014 at 15:38
  • for starters, looking at the first line: I see no reason to use -f, to overwrite output device or partition or -n, to avoid splitting or retrying failed blocks. The ability to split and retry failed blocks is the entire reason to use ddrescue IMHO. Honestly I don't see anything in your question that would indicate the need for any switches (well -r 3 is permissible if you truly want to limit retries to 3, but I wouldn't personally use that switch either) Keep in mind you will need enough available storage to save the entire device chosen as input on the output (/dev/sda or /dev/sda5)
    – Elder Geek
    Oct 19, 2014 at 14:43

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