One or two years ago, we needed more space on one of our servers which was already physically full. We plugged in an external USB drive (actually a Maxtor drive inside an IDE/USB box). Since then, we often lose the drive. Kernel can no longer read partition table. We then need to power cycle the drive to get it back but the server is 800Km away from us.
The strange part is that almost everything is still there, but shifted by 16 bytes ! The MBR is not ours (instead of having LILO string, we can read Invalid partition table.Error loading operating system.Missing operating system).
We tried a lot of things on the USB side without effect (reset, disconnect, change power state, ...).
Today I made some experiments regarding the 16 bytes issue :
losetup /dev/loop0 /dev/sdc -o 16 allowed reading the partition table again.
losetup /dev/loop0 /dev/sdc -o $((63*512+16)) and the vgscan found the volume group !
I can see the data on the disk, however I still could not mount the partitions. Kernel says scsi3 (0:0): rejecting I/O to dead device (Update: this issue was because I don't masterize lvm, after cleanly doing everything, it works fine with this trick...).
It looks like this is a Maxtor issue as the other reports I could find were on same model of Maxtor disk (B200P0), but even if some people see it under Windows they only replied us that they do not support Linux. I also found another report under Debian.
If someone has an idea regarding what's going on, we're really interested :-)