Backing up your Partition Table.

by Talk about Deal on Jul.05, 2009, under Blog

You don’t want your data go unsafe, don’t you?
This one is common problem, getting your partition table corrupt.

So I always keep a Backup of it.
Which is more than easy, I’m using dd command, which for coping/converting/cloning/and imaging the file.
So the drives, because everything in Linux is file, except your NIC.

For those who don’t know where is the partition table, –
Partition table is a part of your MBR ( Master Boot Record )
The MBR size totals to 512 byte ( 1 Byte = 8 Bits, 1 Byte is used to store one binary value either 0 or 1 )
The Structure of MBR is like this

Address (Decimal)	Content	Size (Bytes)
0	Code Area	440
440	Optional Disk Signature	4
444	NULL	2
446	Table of Primary Partition	64
510	55h MBR Singnature	1
511	AAh MBR Signature	1

Totaling 512 Bytes

First, We will back up the MBR.

dd if=/dev/hda of=mbr.bak bs=512 count=1


Now to Restore the Backup MBR

dd if=mbr.bak of=/dev/hda skip=446 seek=446 bs=1 count=64

/dev/hda might change as per your Hard Drive setup. 
For SCSI drives it will list as /dev/sda 
To List your drives and partition 
You can always use fdisk –l

Technorati Tags: MBR, Partition Table, Backup, Linux, dd, How To