Recovering from corrupted SCSI disk

Kurt Hansen khansen at charityweb.net
Thu Jul 29 18:40:55 UTC 2004


Hi,

In upgrading my Dell Precision 410 workstation from RH 7.2 to FC2, my 
primary SCSI hard disk was corrupted.

The corrupted disk, /dev/sda, had 2 or 3 FAT32 partitions and one ext3 
partition, I believe. The FAT32 held Win2K, and the other was a Linux 
partition.

I don't really care about the FAT32 partitions, but I'd like to get the 
data from the linux partition. I don't think it is corrupted at all, but 
the partition table, the MBR, and early cylinders are. The linux 
partition holds about 3.1 GB of data.

I'm hoping that I can copy that data via ftp to another machine that has 
space. Then, I could just do a low-level format of the drive and try 
again. After much searching, though, I still haven't figured out how to 
get to this data. Any ideas?

More background:

I tried first to do an upgrade, but ran into disk space problems. Most 
of my Linux install on this machine is on a second drive, including the 
/boot partition. That second drive seems to be just fine.

So, I decided to just install FC2 over Win2k and forget about the 
dual-boot. I chose to do a manual partition to preserve all the Linux 
partitions and move the /boot and GRUB to the first drive. I got some 
warning messages, but the messages also said that it would only be a 
problem for older boot loaders. Thus, I forged ahead, creating a /boot 
partition, a / partition, and a /usr/local partition out of the old 
Windows ones. All were ext3.

After choosing the packages and beginning the install, the installation 
stopped and exited abnormally. The partition table had been rewritten, 
but I'm not sure how much further it got. I tried to install again and 
re-partition, but it wouldn't let me.

Then, I re-booted into linux rescue mode and tried to partition the 
drive using fdisk. Big mistake. After leaving fdisk telling it to write 
(w) the partition table, I then triend to look at it again to make sure 
the partition table was correct. Now, what I get is:

Unable to read /dev/sda

I do sfdisk -l /dev/sda and get:

130 cylinders instead of 1110
read: input/output error
cannot read sector 0
unrecognized partition
No partitions found

I've tried gpart, but it fails with the error "cannot get sector size on 
dev(/dev/sda)" even when I give it the geometry using -C 1110,255,63

I should be able to boot into RH7.2, once I figure out how to make the 
second disk the first disk. I have to read up on that, but if anybody 
knows off the top of their head, thanks!

Thanks!

Kurt Hansen
khansen at charityweb.net





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