Disk doesn't contain a valid partition table
 

Does anyone have any idea why I keep finding Disk /dev/sdd doesn't contain a valid partition table and the USB drive will not mount? The drive can be working one day and fail the next. Since this happens with two drives I do not think this is specific to the drive.

To fix the problem I have tried running fsck /dev/hdd but the message back is

fsck /dev/sdd
fsck 1.40-WIP (14-Nov-2006)
e2fsck 1.40-WIP (14-Nov-2006)
Couldn't find ext2 superblock, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sdd

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>

which is a bit strange since the drive is formatted to ext3.


fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 2550 20482843+ c W95 FAT32 (LBA)
/dev/sda2 2551 2805 2048287+ 82 Linux swap / Solaris
/dev/sda3 2806 9052 50179027+ 83 Linux
/dev/sda4 9053 9729 5438002+ f W95 Ext'd (LBA)
/dev/sda5 9053 9729 5437971 83 Linux

Disk /dev/sdb: 200.0 GB, 200049647616 bytes
255 heads, 63 sectors/track, 24321 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 1 12493 100349991 83 Linux
/dev/sdb2 12494 24321 95008410 f W95 Ext'd (LBA)
/dev/sdb5 12494 19946 59866191 83 Linux
/dev/sdb6 19947 20711 6144831 b W95 FAT32
/dev/sdb7 20712 24321 28997293+ b W95 FAT32

Disk /dev/sdc: 200.0 GB, 200049647616 bytes
255 heads, 63 sectors/track, 24321 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdc1 1 9023 72477216 c W95 FAT32 (LBA)
/dev/sdc2 9024 24321 122881185 f W95 Ext'd (LBA)
/dev/sdc5 9024 24321 122881153+ 83 Linux

Disk /dev/sdd: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdd doesn't contain a valid partition table


So I would like to understand what is the problem. I had thought from reading round google I got the idea that this was related to writing and deleting large amounts of data on a USB drive but I now think this is not the case since on the latest failure the drive has not been used ... powered down and the following day powered up.

Are you unmounting the drives before powering them down?

Not strange at all - ext3 is just ext2 plus a journal. Try an alternate superblock as it suggests

Assuming that is not a typo you need to specify the partition device ID and not the drive's. i.e.
fsck /dev/sdd1

I also assume that your not trying to run the fsck command on a mounted partition. AFAIK running the command using /dev/sdd should not of damaged the partition table. Do both drives output the same error i.e. no valid partition table?

{BBI}Nexus{BBI} - Yes, the drives are unmounted and powered down before shutting down the computer.

syg00 - yes I have tried running the command but it does not have any effect.

Do you happen to know why this happens?

michaelk - erm ... actually it was a "senior moment" but the effect is the same ... it will not run and gives the message about the superblock. The command suggested in that message also will not run .... The drive cannot be mounted so I am sure that it is not a problem from that respect.

I do not know if it is a related event or not but the system took just over an hour to boot this morning. This is without any USB device being connected.

FSCK kicked in to scan all drives and volumes, this is what took the time. There were lots and lots of problems. Messages like "Port Failed to Respond (30 secs status 0xd0" and "revalidation failed (errno=-2)" and I/O errors relating to one of the drives.

I just wonder what on earth is going on and whether the two events are related at all.

michaelk was on the right track - fsck needs to be run against a partition not a device.
As for why it happens - no idea. Normally I'd say the disk is on the way out, but if it happens on multiple devices maybe the (USB) controller chip is suspect.

USB controller chip .... good suggestion. If that is the case then this would make the two events (todays startup problem and the external drives) as separate events.

Whatever I find out I will be making a very up to date backup of all data before I power down this machine today ....