[ILUG] disk recovery

[Kae Verens]

hi all,

two days ago, I went to read a file on one of my archive disks, shared through NFS by a machine in the attic. the root 
directory showed the right number of files, but most of the file names were garbled.

I didn't spot that for a moment, and tried to go into the directory I wanted ('/b'), but it claimed it was a file. then 
I noticed the garbled files.

restarted the machine in case it was something simple. drive didn't turn up.

went upstairs and checked. the drive was very hot, so I guess that was the culprit. turned it off and left it over night.

next day, checked, and the main partition was missing (/dev/sdc did not have child /dev/sdc1 node), and fdisk claimed 
the drive was 80GB, even though it's actually 200GB.

today, I check again, and fdisk claims it's 200GB, but the partitions are still missing.

went into fdisk to rebuild them:

 > [root at localhost ~]# fdisk /dev/sdc
 > Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
 > Building a new DOS disklabel with disk identifier 0xb97626c7.
 > Changes will remain in memory only, until you decide to write them.
 > After that, of course, the previous content won't be recoverable.
 >
 >
 > The number of cylinders for this disk is set to 24792.
 > There is nothing wrong with that, but this is larger than 1024,
 > and could in certain setups cause problems with:
 > 1) software that runs at boot time (e.g., old versions of LILO)
 > 2) booting and partitioning software from other OSs
 >    (e.g., DOS FDISK, OS/2 FDISK)
 > Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
 >
 > Command (m for help): p
 >
 > Disk /dev/sdc: 203.9 GB, 203928109056 bytes
 > 255 heads, 63 sectors/track, 24792 cylinders
 > Units = cylinders of 16065 * 512 = 8225280 bytes
 > Disk identifier: 0xb97626c7
 >
 >    Device Boot      Start         End      Blocks   Id  System
 >

no partitions.

so rebuilt and saved:

 > Command (m for help): n
 > Command action
 >    e   extended
 >    p   primary partition (1-4)
 > p
 > Partition number (1-4): 1
 > First cylinder (1-24792, default 1):
 > Using default value 1
 > Last cylinder, +cylinders or +size{K,M,G} (1-24792, default 24792):
 > Using default value 24792
 >
 > Command (m for help): p
 >
 > Disk /dev/sdc: 203.9 GB, 203928109056 bytes
 > 255 heads, 63 sectors/track, 24792 cylinders
 > Units = cylinders of 16065 * 512 = 8225280 bytes
 > Disk identifier: 0xb97626c7
 >
 >    Device Boot      Start         End      Blocks   Id  System
 > /dev/sdc1               1       24792   199141708+  83  Linux
 >
 > Command (m for help): w
 > The partition table has been altered!
 >
 > Calling ioctl() to re-read partition table.
 > Syncing disks.
 > [root at localhost ~]#

fine enough. now let's look again:

 > [root at localhost ~]# fdisk /dev/sdc
 > Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
 > Building a new DOS disklabel with disk identifier 0x4de23cfd.
 > Changes will remain in memory only, until you decide to write them.
 > After that, of course, the previous content won't be recoverable.
 >
 >
 > The number of cylinders for this disk is set to 24792.
 > There is nothing wrong with that, but this is larger than 1024,
 > and could in certain setups cause problems with:
 > 1) software that runs at boot time (e.g., old versions of LILO)
 > 2) booting and partitioning software from other OSs
 >    (e.g., DOS FDISK, OS/2 FDISK)
 > Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
 >
 > Command (m for help): p
 >
 > Disk /dev/sdc: 203.9 GB, 203928109056 bytes
 > 255 heads, 63 sectors/track, 24792 cylinders
 > Units = cylinders of 16065 * 512 = 8225280 bytes
 > Disk identifier: 0x4de23cfd
 >
 >    Device Boot      Start         End      Blocks   Id  System
 >
 > Command (m for help):

still no partitions. nothing else I can think of until I can at least rebuilt the partition table.

any ideas? it's a Maxtor DiamondMax 10, 200GB PATA133 HDD, held in a Canyon external USB caddy.

kae