Hello. I'm trying to create a sparse image/loopback device with DD to match my physical two terabyte HD, but I'm not sure how to properly calculate block size and seek settings. Any assistance on what the correct setting would be so that it matches exactly to my HD would be greatly appreciated. This is for use with ZFS on Ubuntu. I'm transitioning a ZFS mirror to a raid-z, and need to use a sparse image to create the raid-z, which I can then detach and use the pool degraded until I can get my data copied over. Thank you for any assistance!

The fdisk -lu output for one of my 2TB drives is:

Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168
sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

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

I have no idea exactly how to do this but here are two threads that might get you started until someone more knowledgeable comes along: http://www.linuxquestions.org/questi...ml#post2679562

http://www.linuxquestions.org/questi...ommand-362506/