New external harddrive and 106Mb unallocated - why

[Chris Murphy]

On Dec 30, 2013, at 4:22 PM, Robert Moskowitz <rgm at htt-consult.com> wrote:

> I just got a Toshiba Canvio Desk 2TB external HD that my plans are to delete the NTFS partition and put on an EXT4 one.
> 
> Thing is the first 106MB are unallocated.  Why?

Can you post the results from 'parted -l /dev/sdX u s p' that might be useful. This was new in box?

> 
> If this was a Chinese product, I would be worried.  I actually found a 'call home' USB stick once.  One MIGHT think that Toshiba has decent quality control.  But why the unallocated space; is this for sector replacement?

Those are hidden on modern drives. When a physical sector is replaced, it no longer has an LBA, it's reassigned to the replacement. It's one of the reasons zeroing drives is an almost pointless security task because substituted sectors still contain data and are erase only the ATA Security Erase functions.

> Seems to be a rather nice unit.  Drive did not power up until I connected the USB; very convient not to have to unplug it to save on power usage.

I see, it's in an enclosure, so chances are this is some weirdness on the part of the vendor who partitioned and pre-formatted the drive, rather than something the OEM did. I'm a nut, so I'd pull the drive, SATA or eSATA it to a board, and ATA Secure Erase the thing, take a baseline smartctl -x sample, put it back into its enclosure, and then GPT partition and format it.

I might even go so far as to use gdisk to partition it twice, once outside and once inside the enclosure, and make sure the relevant data are identical, in particular the number of physical sectors. There are some enclosure firmware floating around that misreport the size of the drive so you end up with a drive partitioned one way in the enclosure and yet the backup partition is reported as missing or damaged when pulled from the enclosure. Such enclosure deserve to be returned as defective.

Chris Murphy