repair damaged Partition Table

cccc · 05-31-2013, 10:04 AM

Hi

Howto repair damaged Partition Table with Ext4 on Wheezy?

pan64 · 05-31-2013, 10:06 AM

what have you tried? probably testdisk will help you,

cccc · 05-31-2013, 01:53 PM

Quote:

Originally Posted by pan64

what have you tried? probably testdisk will help you,

By mistake, a very important Ext4 70 GB partition was overwritten with a FAT32 1GB partition with some files from Debian Live USB.
Do you think, I still can recover files from a damaged Ext4 partition?

BTW I've already tried testdisk, but cannot find files from damaged Ext4 partition.

PTrenholme · 05-31-2013, 03:57 PM

photorec doesn't rely on the partition table, so it can sometimes find some files.

parted, in the "advanced" menu, has an option to rebuild a damaged partition table, but - from your description - it sounds like the table was overwritten, not just damaged, so that's not likely to help.

BEFORE YOU TRY ANY RECOVERY, I'D STRONGLY SUGGEST IMAGING THE ENTIRE DISK AND WORKING WITH THE IMAGE.

That way you won't make things worse and, if you really need to recover files, you can send the drive to a commercial recovery shop. (Note that this is a VERY expensive option, since you'll be employing well trained technicians to, basically, do a byte-by-byte examination of the drive, sometimes by hand. I.e., weeks or months at $100-$200/hr.)

cccc · 05-31-2013, 04:14 PM

Quote:

Originally Posted by PTrenholme

photorec
BEFORE YOU TRY ANY RECOVERY, I'D STRONGLY SUGGEST IMAGING THE ENTIRE DISK AND WORKING WITH THE IMAGE.

That way you won't make things worse and, if you really need to recover files, you can send the drive to a commercial recovery shop. (Note that this is a VERY expensive option, since you'll be employing well trained technicians to, basically, do a byte-by-byte examination of the drive, sometimes by hand. I.e., weeks or months at $100-$200/hr.)

BTW I have an Acronis Image of the whole disk, but it's 2 weeks old and I have quite important new data. It will be lot of work to create again.

pan64 · 06-03-2013, 01:05 AM

So old data and probably part of the structure can be recovered by that image, I do not know Acronis, but probably filesystem can also be restored. Data saved after the last backup can be restored by testdisk I would suggest you to save the content of the disk (with dd) and try to recover from that backup.

Hangaber · 06-03-2013, 11:38 AM

A few months back, I was able to recover a few extra files (that testdisk did not) using "extundelete".

However, if any of these files are over 4GB (not the image/partition, but the files you wish to recover), you will have to modify the source code and rebuild.
Per: http://sourceforge.net/mailarchive/f...undelete-users

Code:

...the source code and changed line 2534 in extundelete.c from
 if (truncate( (outputdir + fname2).c_str(), EXT2_I_SIZE(inode)) == 0) {
to
 if (1 || truncate( (outputdir + fname2).c_str(), EXT2_I_SIZE(inode)) == 0) {

I didn't perform the recompile on Debian though ... although your issue is not Wheezy specific, it just happens to be the OS you're using.
(You can attempt recover those files using any compatible OS, including a bootable-CD/thumbdrive based live OS.)