DSM-G600, DNS-3xx and NSA-220 Hack Forum

cail · 2010-08-02 01:13:11

Hi all,

My dns323 worked like a monster for at most two years, until recently it fall down from about half a meter (my small daughters have something to do with this accident)..

I had only a single 750Gb WD drive configuration (shame on me), and after this it failed to load. First boots were successful, but showed big number of bad sectors in dmesg logs, then lights go into pink and it become dead with all the data.

Now I've got a new 1Tb replacement, and trying to recover the stuff. Strange, but the failed one being plugged into second slot, first rejected to be mounted, but later I've been able to mount it manually, and what is exciting it now even mounted by DNS itself. Looks like some sector remapping took place after some time and FS structure is not corrupted.

What I have now although, is a disc filled with important data which I'm trying to recover onto a good disk. The problem is that because of bad sectors I can't quickly copy the stuff.
Doing cp or rsync runs fine, until bad sector is found. then things become slow as it finds more and more bads within same file.

What I'm lookin for is an ability to quickly detect all "bad" files, isolate them, quickly copy all the good stuff left. Then, if having a list of bad file names, I could manage to recover them from some backups I have. Does anybody knows of any tool for this? The best thing I've found till now is this HOWTO: http://smartmontools.sourceforge.net/badblockhowto.html
The problem there is that it requires to manually perform filesystem lookup actions - this is not acceptable for the 750Gb of data I have.

Another question (think its abstract) is is it possible to force to remap or disable all the bad sectors - f.e. just to use this drive for some time as a backup? I've heard that writes onto bad sectors force the drive to remap. Is this feasible?

Thanks for any ideas or comments, in advance.

Last edited by cail (2010-08-02 01:13:44)

Grunt · 2010-08-02 03:58:53

You'd better do backup an image of your 750Gb drive, on the 1Tb one, using "dd_rescue", a DiscDump tool able to accept bad sectors.

dd_rescue is able to give up on bad sectors and keeping on reading, and will create a "bit by bit", excepting bad sectors, exact copy of your drive.

You need to plug in your drive in a machine you get a full access on it, so that you could use ddrescue.

So:
- plug the 750 Gb drive in a PC,
- plug also the 1Tb drive,
- better use a dedicated operating system as SystemRescueCD.

It's important, and the first thing to do, to have a copy of all usable datas on a "clean" drive, before doing anything. Your 750Gb drive could definitly die now, or while trying to recover datas.

Last edited by Grunt (2010-08-02 03:59:31)

cail · 2010-08-03 21:38:23

Thanks alot for the reference, think this is exactly what I've searched on "rescue" software but didn't found.

However, I've already manually half-copied the content, moreover I don't have access to any PC to try to perform the above cloning. For future I'll for sure use ddrescue.

cail · 2010-08-29 23:48:57

After a while, I've got another dying drive from my laptop. Although its a 3.5" sized, it attaches fine to DNS323. And since I have no other box to play with this bad drive, I've recompiled ddrescue for DNS323. Probably It'll be useful to somebody else.

Attached is a dd_rescue 1.12 compiled.

Attachments:

ddrescue-dns323-binary.tgz, Size: 50,345 bytes, Downloads: 200

DSM-G600, DNS-3xx and NSA-220 Hack Forum

Announcement

#1 2010-08-02 01:13:11

Bad sectors - how to efficiently save data?

#2 2010-08-02 03:58:53

Re: Bad sectors - how to efficiently save data?

#3 2010-08-03 21:38:23

Re: Bad sectors - how to efficiently save data?

#4 2010-08-29 23:48:57

Re: Bad sectors - how to efficiently save data?

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