Recovering large hard drives with DD

roncarney · 05-03-2005, 02:10 PM

I have a hard drive that is unmountable. I want to DD the whole thing to another drive, but I hit the 4gb limit, and the drive is over 120gb, even though at most 2/3 of that is used. Is there any way to get past the 4gb limit to recover the data on the drive? Is dd even the best way to do this?

Thanks
Ron

madluther · 05-03-2005, 02:15 PM

dd has no 4GB size limit, I regularly use it to clone drives of 70GB or more.

Mad

roncarney · 05-03-2005, 02:18 PM

Thats encouraging; then what is giving me the error :File Size Limit Exceeded when the dd hits 4gb? Do I need to tweak the kernel for large file support?

benjithegreat98 · 05-03-2005, 02:24 PM

Can you give us the command you used to mirror? I tried to mirror a drive to a .iso file on a fat32 drive and forgot about the fat32 limit of 4gb files.

So show us what you are typing to accomplish this, please.

roncarney · 05-03-2005, 02:32 PM

I am trying to recover data from a 120GB hard drive that WIndows can no longer access. Linux can see the drive, but cannot mount it. The drive is NTFS.
I tried the following:
dd if=/dev/hde of=/media/WD_Combo/recovery/img1.iso

where WD_Combe is a fat32 drive - so thats the limit? If I reformat the target drive in ext3 will it be able to copy with no size limit?
Also, if I do copy all the data to the ISO file, how do I get it back to a usable format? I am only used to using ISO's to burn/rip CD's...

Thanks

madluther · 05-03-2005, 02:41 PM

Yes, the problem is the target iso is being copied to a partition with a 4GB file size limit, using ext3 will solve that problem

To copy the data back to a new drive

dd if=/location/of/img1.iso of=/dev/hde

or you could even mount the iso itself

mount -o loop -t auto img1.iso /mount/point

that last command will require loopback device and NTFS support in your kernel.

Mad.

xhypno · 05-03-2005, 03:41 PM

Why not just recompile your Kernel to support NTFS and mount the drive directly?

If not, dumping ot an ISO is the best route.