Note: This situation is evolving. Please see the output at the end of this question for the current situation.
I'm using Linux Mint 14. Recently, I repartitioned one of my hard drives, and I backed up all my data to an external USB 500GB drive. Now I am trying to copy that data back.
However, the drive is behaving strangely. When I plug it in, it shows up on my desktop:
… but when I right click and select to view "Properties", underneath the "Permissions" tab, it says:
The permissions of "USB500" could not be determined.
Also, it shows that 359.7 GB of the drive is used, which is about the right amount for the data I backed up:
… but, when look into the drive, most of the files are not visible to me. For example, when I look at the properties of the "dave" directory, where most of my files are backed up, it says it's only 1.3 MB in size:
There should be more like 300GB in that folder.
Why are most of my files seemingly missing when the data used on disk is so much larger? Why is the permissions not determined?
Most importantly, what is the safest process for me to diagnose problems and retrieve the data off this disk?
Update: This output was requested in an answer below:
$ mount | grep USB500
/dev/sdd1 on /media/dave/USB500 type ext4 (rw,nosuid,nodev,uhelper=udisks2)
When I ran the following command, I got a huge stream of lines that ended with Input/output error (too many to reproduce here, but they're all basically the same):
$ sudo find /media/dave/USB500 -ls | less
find: `/media/dave/USB500/dave/.guayadeque': Input/output error
find: `/media/dave/USB500/dave/.compiz-1': Input/output error
find: `/media/dave/USB500/dave/.anthy': Input/output error
find: `/media/dave/USB500/dave/.compiz': Input/output error
find: `/media/dave/USB500/dave/Apache_Logs': Input/output error
find: `/media/dave/USB500/dave/.avidemux': Input/output error
find: `/media/dave/USB500/dave/.dvdrip': Input/output error
On the one hand, this seems to indicate a possible hardware failure(?). On the other hand, it is listing all the files I'm hoping to recover… so is it possible they are accessible? I really hope so…
Update 2: I tried running fsck in hopes of repairing the drive and recovering at least some data, but I got this response:
$ sudo fsck -y /dev/sdb
fsck from util-linux 2.20.1
e2fsck 1.42.5 (29-Jul-2012)
fsck.ext2: Attempt to read block from filesystem resulted in short read while trying to open /dev/sdb
Could this be a zero-length partition?
Sometimes the drive does not seem to mount, I have not determined a pattern as to what causes it to become un-mountable. After turning it off and on, or after a reboot, I seem to be able to get it back.
I removed the hard drive from it's USB interface and connected it to the computer's internal P/SATA bus, but it seemed that the drive behaved exactly the same, with identical symptoms.
I believe this drive is dying, so right now the goal is to try to find some way to access the data that should be there just long enough to copy as much of it as possible. Suggestions on how I might do that would be most appreciated. There are actually just a few key directories I would like to access, so hopefully, if the failure is not too global, I might be able to get what I need.
Update 3: I'm currently running the following command. I started it a day ago, and it's still going. I hope it is doing something useful. If anyone can confirm for me what the output below indicates about its progress, that would be very helpful.
$ sudo ddrescue -r3 /dev/sdb /home/dave/RECOVERY/usb500.image
/home/dave/recovery_usb500.logfile
Press Ctrl-C to interrupt
Initial status (read from logfile)
rescued: 0 B, errsize: 0 B, errors: 0
Current status
rescued: 0 B, errsize: 500 GB, current rate: 0 B/s
ipos: 5366 MB, errors: 1, average rate: 0 B/s
opos: 5366 MB, time from last successful read: 1 d
Splitting failed blocks...
Best Answer
I think your next steps depend on how valuable the data on the drive is.
If its fairly valuable, your next step should be to stop attempting recovery and instead contact a data recovery firm. Hopefully it's just the electronics on the PCB failing, in which case they ought to be able to do a full recovery relatively inexpensively.
If you're not going to do that, your goal should be to get an image of as many sectors as you can from the failing drive. (You'll need a drive larger than 500GB to store it, but that shouldn't be a problem).
If you have an exactly identical drive (that works), you could try borrowing the PCB from the working drive. You'll want to practice swapping the PCBs on drives that don't contain important data first, to make sure you know what you're doing.
Otherwise, you can try tools like
dd_rescue/myrescue/gddrescue/etc. It may be that the drive works for a bit, then completely dies, in which case you'll have to do many passes, getting more sectors each reset/power cycle.Once you have an image of the drive, your next step is to make a copy of that image, and work on the copy.
I'd suggest you try to
fsckthe copy, then loop mount it.