Comments on: Linux: How to backup hard disk partition table (MBR)

By: Marek

Marek — Wed, 07 Dec 2011 11:19:15 +0000

What about GPT ?

By: Mr_T

Mr_T — Tue, 13 Sep 2011 19:31:39 +0000

Victor,
In your first post, could you clarify the units you are using for mbr and the partiton table and what is the “2 as end” means. Its not intuitive to the uninitiated.

Thanks

By: victor

victor — Sat, 03 Sep 2011 12:45:59 +0000

i’m sorry, i’m mistake. error coud be if mbr is all zero. then you must add conv=notrunc for no file optimization.
ej:
2GB file
dd if=/dev/zero of=afile bs=1 seek=2GB count=1 (file size in hd<1kb)
or
dd if=/dev/zero of=afile bs=1 count=2GB (file size in hd=2gb)

size must be specific in bytes, 2gb is only for easy read.
note: a little bs spend more time

By: victor

victor — Sat, 03 Sep 2011 12:18:51 +0000

jns, it could be because only one seek is needed.
there are 446b of MBR, 64b of Partition Table and 2 as end (0x55aa). {= 512b}
if skip and seek aren’t synonimous, you seek 446 + 446.
thus, command line must be
dd if=sda-mbr.bin of=/dev/sdX bs=1 count=64 skip=446
or
dd if=sda-mbr.bin of=/dev/sdX bs=1 count=64 seek=446

By: jns

jns — Mon, 22 Aug 2011 06:07:32 +0000

The restore line corrupted my entire partition table…
beware, i guess…

By: VernDog

VernDog — Wed, 26 Jan 2011 16:26:50 +0000

Wrong! This method DOES WORK with extended , primary partitions. I’ve used it all the time, to both backup & restore. Just remember to backup MBR if you add any changes to partitions.

By: Jack

Jack — Sat, 09 Oct 2010 09:47:33 +0000

PT,

You can use sfdisk to backup extended partition table.

sfdisk -d /dev/sdX > backup-sdX.sf

Restore:

sfdisk /dev/sdX < backup-sdX.sf

By: PT

PT — Tue, 10 Aug 2010 05:14:04 +0000

This advice does not work if you have an extended partition table.

By: Wartin

Wartin — Thu, 15 Apr 2010 13:37:17 +0000

dd if= sda-mbr.bin

it has a blank space after =, it should read

dd if=sda-mbr.bin of=/dev/sdX bs=1 count=64 skip=446 seek=446